Download Energy - Physics A to Z

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is for Antimatter
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In particle physics, antimatter is the mirror of matter; for every particle there is an
antiparticle and when they meet they annihilate one another, resulting in a burst of pure energy.
Einstein came up with the famous equation E=mc 2 . This equation relates energy to mass via "C" where c is
the speed of light (a very large number). This means that extremely large quantities of energy are equivalent
to quite small quantities of matter. For example, the energy contained in a single grain of sand is equivalent
to the chemical energy in about half a tank of gas. When antimatter and matter annihilate they are converted
to energy according to E=mc 2 . The discovery of matter-antimatter annihilation has helped confirm Einstein's
equation.
matter
=
energy
(3 x 108 m/s)2
Antimatter is made of antiparticles, just like
normal matter: an antitthydrogen atom is composed of an antiproton and an antielectron (a
positron).
anti-hydrogen
The fact that the normal-matter universe exists at all is one that has baffled physicists for years.
If nature provides an antiparticle for every particle, and they annihilate on contact, then the entire universe
should be matter-less and composed of gamma rays. Physicists theorize that there must have been a slight
imbalance of matter to antimatter creation in the few seconds after the Big Bang. Calculations accounting for
the current matter in the universe show that the imbalance can actually be explained by one extra mattermatter pair per billion matter-antimatter pairs in the early universe.
This process is called baryogenesis:
~ Erwin Schrodinger and Werner Heisenberg present the new
~ quantum theory of physics, however the theory was not
1,000,000,000 (e- + e+)
relativistic (did not address particles traveling at light speed)
~
~
~
Albert Einstein unveils his theory of Special
Relativity, explaining the relationship between
space and time "'--~"""'!""ll"""-III
~
Paul Dirac combines quantum theory and special
relativity to describe the behavior of the electron
Dirac's equation, like x2 =4, has two solutions: one for an
electron with a positive energy, and one for an electron
with a negative energy. Dirac interpreted this to mean
that for every particle there is an antiparticle!
~
Ernest Lawrence invents the cyclotron
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N
Carl Anderson observes and christens
~ positrons while studying showers of
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cosmic particles in a cloud chamber
Antiparticles occur naturally as a product of high-energy collisions, like those in Earth's atmosphere,
but can be produced artificially using an accelerator. A particle accelerator bounces a normal
matter particle between differently charged electromagnets until it is moving as
close to the speed of light as possible, and then smashes the particle
against a target to produce antimatter. Physicists study
Each electromagnet
these collisions to learn more about antimatter
is longer than the previous,
and how it behaves.
which accelerates the particle. The
particle's frequency remains constant: it has to
"jump" to the next magnet in a set time, meaning its
velocity increases as the lengths of the magnets increase.
....---""-----.......
electromagnet
Antimatter drives are popular in SciFi because of their high energy
potential and conversion purity. When antimatter and matter
collide they convert to gamma radiation, which is very
energy-dense (containing approximately 5 million times as much
energy as visible light). However, we cannot yet produce enough
antimatter to be used as fuel- the number of antiprotons produced in
the US in one year could only power a 100 watt light bulb for about 30 seconds! Storing
antimatter is also difficult. Currently, there is research being done on electro-magnetic
containment, but antimatter drive is still a thing of the future.
A practical application of antimatter is Postron Emission Tomography, or PET
scanning. This technique uses electron-positron annihilations, which are
relatively low-energy, to reveal the workings of the brain. These positrons
come from the decay of radioactive nuclei that are incorporated in a special
fluid injected into the patient. The positrons then annihilate with electrons
in nearby atoms.
Since the electron and positron are almost at rest when they annihilate,
there is not enough annihilation energy to make a particle and antiparticle
and the energy emerges as two gamma rays. The gamma rays shoot off in
opposite directions and are detectable. Physicians can deduce that in places
where there are more of these annihilations there are more electrons and
therefore more brain activity.
~ Lawrence builds the Bevatron at Berkeley,
~
which could collide two protons at 6.2 GeV,
expected to produce antiprotons
~ Antiproton produced and detected by
~ Ernest Lawrence and Emilio Segre
~Team at Berkeley announces
~ discovery of the antineutron
tBTwo teams observe the antideuteron
~ (an anti nuclei comprised of an
antiproton and an antineutron)
~
~
Team of German and Italian
physicists slow anti nuclei
and positrons to force them
to create antiatoms (9 antihydrogen atoms created)
The Beginning of Our Universe
Some of the bigest questions have been: How did we get here? Where did we come
from? Where are we going? People called Steady State Theorists believe that our universe has
been around forever and is infinite, but through the theory of the Big Bang, assuming that the
universe is infinite is wrong. The Big Bang Theory suggests that the whole universe came
from one initial explosion tht laid out the foundations of the universe. The Big Bang
happened about 15 billion years ago and expanded the whole unverse to what it
is today. One of the biggest arguments that the Steady State Theory doesn't
stand up to is the idea that every galaxy in the universe moves at a directly
proportional rate to one another. If the galaxies move at this rate, if this rate
is reversed, it would lead to every galaxy coming from one central place and time.
The Age of Our Universe
In 1936, Edwin Hubble observed two components to finding out how old our universe
is: galaxies' red shifts and galaxies' distances moving away from ours. A red shift is when
a galaxy has a longer wavelength as it moves farther away from our galaxy. Hubble
o
perceived that galaxies that are moving away from each other move at a directly
proportional rate. For example, if a galaxy is twice as far from another galaxy, it's moving
twice as fast as the other one. From this, Hubble figured that if galaxies were moving at
Dr. Edwin Hubble
a directly proportional rate, reversing this process would lead to each galaxy coming from one
place at one time. Hubble measured the distance of the farthest star from our galaxy by its intensity, which
equaled time. This is the equation Hubble used:
distance ofparticular galaxy
particular galaxys red shift
time
with this equation in hand, Hubble plugged in the
numbers:
4.6 X 1026 centimeters
lxl0 9 centimeters/sec
4.6 X 1017 seconds
4.6 X 1017 seconds is equivalent to approximately 15 billion
years.
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A side view of the big bang. As the big bang happened, the universe was
very hot (billions of degrees kelvin !), expanded outward and cooled to its
temperature now (about 3 degrees kelvin).
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The picture below depicts the process of the Big Bang. Here's what happened:
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1. 10-43 seconds, temperature begins: cosmos begin expanding.
2. 10-32 seconds, 10 27 degrees celsius: universe is hot plasma stew full of particles like electrons and quarks.
3. 10-6 seconds, 1013 degrees celsius: protons and neutrons begin forming.
4.3 minutes, 108 degrees celsius: universe is a giant, hot cloud, protons and neutrons are present but is still too
hot to form atoms.
5.300,000 years, 10,000 degrees celsius: Electrons, protons and neutrons combine and create heluim and
hydrogen atoms; light begins to shine.
6.1 billion years, -200 degrees celsius: Gravity makes hydrogen and helium
molecules create giant clouds that soon became protogalaxies.
7. 15 billion years, -270 degrees celsius: Galaxies form together because of the presence of gravity; stars die and
create the planets we know today.
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.
c ~s
for Climate Change
Climate defines the weather patterns across the world. It includes temperature, atmospheric pressure,
humidity, and rainfall. Different locations around the world have varying climates, but there are also
some global trends. These trends can be seen throughout Earth's history over long periods of time, such
as ice ages and global warming. These trends are affected by the orbit of the earth around the sun, the
sun's intensity, and the changes in the efficiency of the Greenhouse Effect.
The Green house Effect
The Greenhouse Effect is what warms the Earth enough to make it habitable by humans. To gain an
understanding of this phenomenon, we must consider the role of the atmosphere in the environment of
our planet. The atmosphere contains greenhouse gasses - gasses that absorb infrared radiation. These
gasses include things like carbon dioxide (C0 2 ), water vapor, methane, and ozone. Visible light from the
sun shines through the atmosphere and warms the Earth. The Earth then emits this heat as infrared
radiation sending it outwards. Greenhouse gasses in the atmosphere stop much of the radiation from
escaping to space by absorbing and re-emitting it. This sends heat energy back to Earth re-warming it.
Some of the sun's rays
are reflected by the
atmosphere
Some of this infrared radiation
leaks through to space
One single chlorine
atom can destroy over
100,000 ozone
molecules!!
When the ozone layer
decreases by 1%, UV
ray exposure to the
earth increases
by 2%.
JA Halons
••
•
•
Without the atmosphere,
infrared radiation emitted
by the Earth wouldn't be
re-absorbed, and the temperature on Earth would
only be 26°F.
Ozane
The Earth hangs in a delicate balance between hot and
cold. An increase or decrease in greenhouse gasses
has the potential to disrupt this balance. First,
consider the Earth without an atmosphere. The
average temperature on Earth would be about 26°F.
The surface of the oceans would be frozen and our
planet would be a completely different place. From an
alternate perspective we can look at the global
warming we are currently experiencing. Many of the
gasses that we emit as industrial byproducts are
greenhouse gasses. This causes the atmosphere to
absorb and emit more infrared radiation, which in turn
warms the Earth. The difference of a few degrees
would cause more water to evaporate sending more
water vapor into the air. Water vapor is one of the
most effective greenhouse gasses; therefore, the more
water vapor, the warmer our Earth's temperature will
climb. Although it may have been simple to start this
process, stopping it is a whole different matter.
The ozone hole affects our climate in a different way. Similar to the
greenhouse effect, sunlight plays a major factor in this phenomenon. In
addition to visible light and infrared radiation, sunlight also consist of
something called ultraviolet (UV) light. Exposure to UV light is what
causes sunburns, skin cancer, and mutations in DNA. This is because the
Ozone molecules are
photons of UV light have much more energy than that of visible light or
drawn as resonance
structures, meaning
infrared radiation. This energy also enables it to break up 02 molecules
the double sigma
in the atmosphere into two separate oxygen atoms. These atoms go on
bond can be on
to attach to non-broken 02 molecules creating 3 , or ozone. The
either side of the
produced ozone is an effective absorber of UV and therefore creates
molecule.
more ozone. In this way, the atmosphere is able to adapt to an increase
or decrease in the intensity of the sun. The more UV that shines toward the earth, the more ozone is
created to protect us from the harmful rays. The opposite is also true, sometimes resulting in
something called an ozone hole. During the winter, the South Pole gets little to no sunlight, so with no
UV to create it, the ozone layer disappears over this region. Unfortunately this is not the only
contributor to ozone depletion. Some believe that pollutants from man made sources such as the
chemical Freon (used in old refrigerators and air conditioning units) can lead to the destruction of
ozone. Freon and some other pollutants contain chlorine, fluorine, and carbon and are called CFCs.
These CFCs are highly stable until they float into the upper atmosphere. There they sit until ultraviolet
rays hit the molecules, causing them to split into single chlorine (CI), fluorine, and carbon atoms.
Chlorine and fluorine are then free to attack the ozone molecules sending them back to the 02 state.
Fortunately, an agreement was made called the Montreal Protocol which has resulted in a drastic drop
in the emissions of CFCs. Here are the reactions that occur between carbon and ozone molecules:
°
cia + cia + sunlight
. . . . CI + CI + O2
Now, the two leftover chlorine atoms are free to attack more ozone molecules and repeat the reactions.
is for Doppler
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Christian Doppler
1803-1853
In 1842, a man named Christian Doppler
discovered that objects that are moving
emit sounds at a different pitch than
things that are stationary. His theory was
that the observed change in frequency of
the sound wave is due to the motion. To
further test his theory, he had 15 trumpeters playa single
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note on a moving train. He observed from the side of the
track. When the train passed him, he was able to measure
the change in pitch and thus quantify what we now call the
The sound waves in the front are scrunched up
and the sound waves in the back are stretched out
to demonstrate that the source of the noise is
moving faster.
Doppler Effect.
The reason that we observe the Doppler Effect can be
explained by using the idea of waves. It is similar to when
you're at the beach, standing in the water, letting the waves
fIUW.int;J
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crash at your feet. The waves will hit you more frequently if
you were to walk toward the waves as opposed to standing
still. The frequency increases when the source and
observer are moving towards each other. If they are
moving apart, the frequency shifts lower.
Redshift
f' ~ f
± Uobserver )
V ± Usource
(V
When the observer is moving towards the source,
you add and when he is moving away, you subtract.
In 1845, Christoph Hendrik discovered that the Doppler Effect
occurs in light waves. Just as sound waves get a frequency shift
when the source is moving, stars that are moving relative to us
give out light that is shifted in frequency. This changes the color
of the light towards blue if the object is moving closer, red if
moving away. Edwin Hubble measured the shift in the light from
distant galaxies and compared it to how far they are from Earth.
The shift is determined by the position of certain
wavelengths due to an element in the star's spectral lines
compared with their position on a "laboratory- produced"
spectrum of colors. If the light is shifted up in frequency we
call this "blue shift" and we conclude that the galaxy is
moving towards us. When the galaxy is moving away the
spectrum moves towards the red side of the spectrum. (red
shift) Hubble found that nearly all galaxies we see are moving
away from us and the speed they are moving at is in direct
proportion to the distance from us. What he concluded
from this is that our universe was made at a single point in
time. This idea has since led to Big Bang theory.
Elie~trfc?y~s~~~~;~l~~y~ither
E
an abundance or an absence of electrons. Electrons, which
are negatively charged sub-atomic particles, drive the modern world. From appliances to
vehicles, all technology relies upon this particle's movement through a circuit. The electrons
move in a current, similar to water's movement in a river, and the activity of electrons in the circuit they
are contained within is measured through a relatively simple equation called Ohm's Law.
Measuring Electric Currents
Georg Simon Ohm, a German physicist, discovered that the voltage in a circuit
is the product of the current and the resistance. Thus:
V=IR
V is voltage, also known as the 'potential difference'. Voltage is similar to
water pressure in a hydraulic pump. I is current (measured in amps), and
refers to the number of electrons passing a specific point in once second.
Finally, R is the resistance (measured in ohms), and it reflects the conductors
resistance to the flow of the electric current.
Electricity moving through a circuit is often compared to water moving in a
hydraulic pump. The amount of water flowing past a point every second can
be compared to amps, while the water pressure is similar to voltage. Finally, the pressure the hydraulic
pump exerts can be compared to a circuit's resistance.
Using Electricity to Do Work
When electricity flows through any material, it naturally encounters resistance.
Materials with low resistance (such as copper) are called conductors,
whereas materials with high resistance (such as rubber) are called
insulators. The resistance extracts energy from electric currents, and
converts it into other forms of energy, often thermal.
In a lightbulb, the filament has a high resistance to the flow ofthe electric
current. As the electric current flows through the filament, the resistance
converts the electric potential difference (volts) into thermal energy
(heat). In a lightbulb, the heat is so intense that the filament glows orange
or white hot, which produces the visible light. Everything has resistance,
(unless you start talking about Superconductors, '5'), and that resistance turns
the electric energy into heat.
~~~~§-; While converting electricity to heat is a simple matter, converting it into kinetic
~
energy is a more complex affair. It involves one of electricity's intrinsic properties:
its innate ability to
electromagnetism.
produce
a magnetic
field.
This trait
is
known
as
Hydroelectric Power
Hydroelectric power is electrical power which is generated by converting the energy of falling water.
Hydropower provides about 96 percent of the renewable energy supply in the United States. Hydroelectric
power plants collect water behind a dam to build up potential energy. Potential energy definition is energy
that is stored within an object. For example, when water is not moving it has potential energy because of
earth's gravity. When water starts moving through a dam, the potential energy is converted into kinetic
energy because the water is moving. Combining potential energy and kinetic energy can make mechanical
energy by moving the water to the turbine.
Modern Hydroelectric Dams
A hydroelectric power plant converts the potential energy of water into electricity using the gravitational
force of falling or flowing water. Water must fall in order to generate power from a stream. The process
begins when water flows through a dam containing turbines. When water starts spinning the turbines, the
turbines will turn on the generators that make electricity and the electricity is transferred to the power
lines.
When constructing a
dam engineers have to
have a highly technical
understading. They have
to gather extensive field
data in order to chose
the best site to design
an excellent safe dam.
Head water
The Formula for
calculating power output
in kilowatts of a
hydroelectric dam is:
KW= 0.0846/E X Q X H
I
Power lines
Potential
Energy
Dam
Q= Water flow, cubic feet
per second
H= Head, feet
E= Efficiency of
hydroelectric plant,
percent divided by 100.
Howa Hydroelectric Turbine Works:
The pictu re to the right is a tu rbi ne that converts the ki netic energy of water
flowing into mechanical energy. The energy that is gathered by the flowing
water is channeled it through a hydroelectric generator. Which converts that
mechanical energy into electricity. The operation of a generator is based on
the principles discovered by Faraday. He found that when a magnet is moved
past a conductor, it causes electricity to flow.
Modern Wind Turbines
A wind turbine is a machine that uses the movement of air to do work. Historically, windmills have been used
to pump water and grind flour. Modern wind turbines focus on
converting wind power into
electricity. The turbine blades are angled for maximum wind
capture and connect to the low
speed shaft. The high speed shaft, which drives the generator, is
connected to the low speed
shaft by a gearing system.
Gears
Catching Wind
Today, we have sensors and motors built into the wind
turbine to make them turn toward the wind. The
anemometer and wind vane make up the sensor. They
report the information to the computer, which then
processes and passes the information to the motor. The
motor moves the turbine.
The formula for calculating the
amount of watts from your
Windmill is:
Pm
=
1
2CpPAV3
Cp - estimated windmill's performance.
A - the swept rotor size
in square meters
V - the mean annual wind speed
Motor
-+-----Tower
How Wind is Created
Wind is created when the sun unevenly heats the land
and the ocean, causing hot air to rise at different rates
over the Earth. This gives rise to areas of high and low
pressure within the atmosphere. The atmosphere tries
to equalize the different areas the different
atmospheric pressures. As the atmosphere tries to
equalize the pressures, air flows from one area to
another.
Pm - the acquired amount of watts.
Modern wind turbines have special brakes to slow the
rotor and to prevent the generator from overheating.
A generator can only reach a certain total amount of output before it becomes inefficient and burns out.
Normally, A wind turbine can only withstand speeds of 35-55 mph {miles per hour}. The brakes
completely stop the wind turbines.
Electromagnetism
Electromagnetism refers to the influences of the electromagnetic force, one of the four fundamental
forces in physics on which all others are based. The electromagnetic force is responsible for things such
as friction, and plays a huge role in our everday lives.
In the same way that masses produce gravitational fields, electric currents create electromagnetic fields.
An electromagnet can easily be made by wrapping a copper wire around a cylinder, and then applying
electric current by connecting the wire to a battery.
All magnets have poles, and electromagnets are no exception. Interestingly, the poles are not influenced
by the geography of the cylinder; instead, it is based upon the movement of the current. This is how
electric motors operate.
Fundamentals of an Electric Motor
N
The electric current
passing through the
nail
created
a
magnetic
charge,
with the north pole
positioned near the
end of the circuit.
S/lN
The north end of the
electromagnet
is
attracted to the south
of
end
of
the
horseshoe
magnet,
and vice-versa, which
causes the nail to
spin.
N
If one subsequently
flips the battery, the
electromagnet's
poles will reverse.
SI""N
As a result, the nail will
flip once more. In an
electric motor, the
"nail"
would
be
attached to an axle.
That way, when the
nail spun, it would spin
the axle.
While this diagram shows the forces at work in an electric motor, it is extremely simplified. In a real
motor, the spinning would drive an axle, which could then drive, for example, a wheel. In addition, the
battery must cycle two times for every rotation, in order to return to the 'initial' position.
Converting Kinetic Energy into Electricity
While electricity can be converted into kinetic energy through electromagnetism, the opposite is also
possible. At its core, everything from nuclear reactors to coal-burning plants use kinetic energy to spin
a turbine, which uses a magnet and copper wire to induce the movement of electricity.
Of particular note are hydroelectric dams and wind turbines, which use ambient energies that would
otherwise go unharnessed.
F Is for Force
Force is an act such as a push or pull that causes an object with mass
to change its acceleration. All forces act in a certain direction and
have a size (or magnitude) based on the strength of the push or pull.
It is impossible to find the force of an object if either the direction
or the magnitude of the force is absent. Mass is important to force
as it can alter the result of an equation. For instance, If an elephant
is being pushed up hill by a mouse, the mouse would need to exert
more force than the elephant, if the roles were flipped.
F=ma
There are various equations used to find the force exerted
on an object. A common force equation is F=ma. F=ma is
used to find the force applied to an object in motion. The
m in the equation stands for mass. The a variable stands
for the acceleration. For instance, if asked what the force
applied on a 1 kg ball being
2
kicked at 10m/s was, the
acceleration would be 10
m/s 2 and the mass would
be lkg. The unit used for
force is the Newton.
One
Newton
is
equivalent to 1
kg m/s 2 . When
you multiply a
mass
which
is measured
in kilograms
by
an
acceleration which is measured in m/s 2, you end
up with kg m/s 2, changing the units to Newtons.
Sir Isaac newton (1642-1727)
Isaac Newton published principa
His book
principa
in 1687.
was
his
most
recognized
peice of work, explaining his
ideas of universal gravity and
the three laws of motion.
Rocket Thrust
Rocket th rust is the force wh ich moves the
rocket through the air
and through space. The
basis of finding out the
thrust force on a rocket
is knowing the mass and
velocity of the hot gas
being burned from the
rocket. As the gas from
the rocket is exerted
from the exhaust, the
rocket
is
propelled
with a forward motion.
What
determines
how fast the rocket is
propelled is how much
gas comes out of the
exhaust and how fast
it is being pushed out.
Gravitational Force
Gravity is defined as a type afforce, as it causes an objects velocity to change when being dropped or thrown
in any direction. Any two objects that have mass, attract each other with a force known
as gravity. The smaller an object in mass the smaller the force exerted. For instance, the
gravity on the Moon is far less than that of
the gravity on Earth, because the Moon has
a smaller mass. This explains the reason
why the Moon revolves around the Earth
and the Earth revolves around the Sun.
•
Torque
It may seem obvious,
but the handles on
doors are placed on
the other side of the
hinges so that it is
easier to turn the
door. If the handle
were to be placed
near the
hinges,
then the door would
require much more
force to tu rn.
Torque is the measure of how much a force causes an
object to rotate rotates around an axis. Torque is defined
as:
T =
r
X
F
The radius (r) is the distance from the axis to the point
where the force is applied. Force (F) refers to the force
that is applied that causes the object to rotate about its
axis of rotation. In other words, torque ("r) is the product of
the radius and the force. Because of this, torque can be
easily increased by increasing the force, or simply increasing the distance from the axis (the radius). This means that
rotating an object will become much easier as there is a
greater radius used to generate the torque.
Torque is generally measured in either pound-foots or
Newton-meters. This is because when measuring force in
pounds, the radius must be measured in feet, and when
measuring force in Newtons, the radius must be measured
in meters.
Some other units such as work are measured by Newtonmeters and foot-pounds (products of force and distance).
Work would refer to force applied in the direction of the
radius. Torque is unique because of the fact that the force
is applied at a right angle to the measured radius.
Using the right hand rule, we can find the direction of
the torque. If we put our fingers in the direction of the
radius (red) and curl them to the direction of the force
(green), then the thumb points in the direction of the
torque (yellow).
Imagine turning a wrench to tighten a bolt.
The force of your pulling causes the wrench
to rotate about the bolt. How hard you need
to pull depends on the distance your hand is
from the bolt. The closer your hand is to the
bolt, the more force it takes to tighten it.
Try balancing a meterstick on top of your
index fingers. When you slowly bring your
two fingers together, you may notice that
they meet at the center eveyry time. This is
because the torque applied by each finger to
keep the stick balanced is different, causing
the frictions to change while the fingers are at
different points on the stick. This is an ideal
example of how friction and torque can work
together to perform phenomonal tasks.
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G
Galileo Galilei (1564-1642)
is for Gravity
The first recorded scientist
to study Gravity. His
experiments involved
dropping objects to see
how they fell.
Acceleration of Gravity
Gravity is an attractive force that occurs between any two objects that have mass. How powerful that force
is depends on how large each mass is, and the distance between them - gravity is stronger for large masses,
and decreases as the objects get further apart. The strength of the force can be found through the following
equation:
F
Gravity is the reason that when you drop an item, it falls to the ground.
The forces between the large mass of the Earth and objects on its surface
are enough to accelerate the objects by a standard rate of 9.8 meters per
second squared. When you drop two items, no matter their mass, you will
see that they accelerate at the same rate and hit the ground at the same
time. This is due mainly to Inertia - a property that any object with mass
exhibits. Even though a large mass has a large force pulling
it to Earth, the object's mass
requires a larger force to move it at
a similar rate to a smaller object.
5.5 kg
Weight
Gravity is a key player in the workings of the universe. It keeps planets in orbit
and provides a basic, yet constant force. One common product of Gravity is
weight. Weight is a measurement of the force towards the center of Earth's
mass, caused by gravity. It can be found by taking the mass of an object and
multiplying it by the acceleration of gravity due to Earth's mass, which as
we established is roughly 9.8 meters per second squared. However your
weight on Earth will not be the same as your weight if you were to stand on
the Moon. Because the Moon has a different mass, it will pull you towards its
center with a different force. Because the Moon's mass is smaller, it would pull
you in with less force, causing you to weigh less on the Moon.
""
The Earth and the Moon
We on Earth feel the pull of the Moon much more than the pull of the Sun (many people think that because
of the tides, the Moon's gravitational pull is the greater). In reality, the force of the Moon's gravity on Earth
is much smaller than that of the Sun's. Think of being on a roller coaster: when you make a turn, you feel the
bumps in the track a lot more than the force of the turn even though the force that you're turning with is
much more than the force from the bumps. We are rotating around the extremely large mass of the Sun, but
as we, the Earth and all things on it are moving together we are unaware of its effect. The force of the Moon
causes a small perturbation to this force (similar to the rollercoaster's bumps) but produces noticeable
effects, such as the tides of the ocean. Tide rotation, where the water levels of the Earth's oceans rise and
fall, is a direct consequence of the Moon pulling mass towards it. Newton correctly
theorized in 1687 that the Moon pulls on the Earth and its water, however the
Moon's force across Earth varies because the Earth is spherical. The side facing
the Moon is under more force than the side away from the moon, thus
stretching the water levels from their spherical shape around the Earth.
Orbit
One of the most visible effects of gravitational attraction is the
tendency of celestial bodies to travel in curved paths around other
objects. A good example of this is the orbit of the planets around Q
the sun. Because the sun has such a large mass (around 333,000 0.;
times the mass of Earth) its gravitational pull attracts all other objects in the solar system. While the planets
in our solar system are in a nearly circular orbit around the Sun, other bodies such as asteroids and comets
travel in elliptical paths around to the Sun. The planet's orbits are relatively stable - circular orbits at different
radii do not cross. An orbit that has the shape of an ellipse will send asteroids close to the sun at one point
and far from it at another. This path may intersect with Earth's orbit, making an impact a real and worrying
possibility.
The Moon's Orbit
When you look up at the Moon in the night sky you notice that its appearance changes from night to night.
As the Moon orbits the Earth, it displays a specific set of characteristics depending on its position relative to
the Earth and the Sun. As seen in the diagram below, there are 8 distinctly recognized stages the Moon goes
through when it orbits around the Earth. The orbit of the Moon is "tidally locked" meaning that frictional
forces occurring from the tides have stopped the moon rotating relative to the Earth. The Moon actually
turns at exactly the same rate that it orbits us, meaning that we see the same portion of the Moon facing us
at all times. The notion of the "Man in the Moon" comes from light and dark regions on the lunar surface
that always appear the same way up.
Phases
It takes around 29 days for the Moon to orbit the
Earth. During this time, the Moon gradually
progresses between phases. It first
starts off as a New Moon, which is
when the Moon is directly between the
Earth and the Sun. At this time the Moon
is not visible from Earth (it appears in the sky
during daytime and only the unlit side faces us). Next is
the waxing crescent, where less than half of the visible
Moon is illuminated. During this phase, more of the visible
side is illuminated each night. The first quarter occurs when the
Moon is directly 90 degrees from the Earth and the Sun. In this position exactly half of the visible Moon is
illuminated. Next is the waxing gibbous, this is when more than half of the visible Moon is illuminated. The
Full Moon is when the Earth is directly between the Moon and the Sun. When the Moon is in this phase, its
visible side is fully lit by the sun. After the Full Moon, the waning gibbous occurs, this is similar to the waxing
gibbous where more half of the visible Moon is illuminated. Before the cycle starts over again, the Moon
goes through a phase similar to the waxing crescent. During this phase, known as the waning crescent, less
than one half of the visible Moon is lit. This final phase can be thought of as a mirror image of the waxing
crescent, but now less of the visible side is lit each night.
is for Hologram
Like photographs, holograms record light onto film. Unlike photographs, when holograms are viewed the
objects in the recording move according to the position of the viewer. This makes the recorded image seem
three-dimensional by creating an illusion of depth and position. In addition, each individual eye picks up a
different facet of the image and the brain combines the two seperate images, further contributing to the
illusion of depth.
Holograms need to be recorded with a specific kind of light known as 'coherent light'. Coherent light is
defined as light whose waves are in phase with each other; this means that the waves are traveling with the
same period and frequency in a parallel motion. In this way coherent light is similar to soldiers marching
in lock step. All are moving together, in the same direction and in step. This differs from the light provided
by ordinary household light bulbs, which glow hot and distrubute random thermal emissions. This light
is 'incoherent;' the light waves can be compared to a shopping mall at Christmas time in which everyone is
moving in all different directions and speeds. The coherent light used to record holograms is provided by a
high power laser.
Coherent Light
Incoherent Light
Lasers create coherent beams by stimulating atoms to emit light. Stimulated atoms have higher energy
electrons and return to a ground state by emitting energy in the form of photons in a laser cavity. These
photons form a beam of monochromatic coherent light. Holograms also require very high resolution film
because patterns recorded onto the film need to be accurate to the wavelength of light. The pixels per inch
(DPI) equivalent of this resolution requirement exceeds 30,000 DPI. That is why holograms currently require
emulsion film.
Laser ••••• -------.
••
•
Beam Splitter
:
Incident Beam
Beam Expander
•
•
•I
••
••
•
•
•
Object
...•..-
I
A beam of coherent light, usually provided
Mirror
by a laser, is directed through a beam expander
I
I
that acts like a reverse telescope. This causes the beam
•
to widen. This beam goes through a beam splitter, a ••••
semi-silvered mirror with a partially reflective surface.
I
Reference Beam----.I
Half of the light goes in one direction to strike the emulsion
film. The other half goes in another direction, off of the object,
and then onto the emlusion film. This is known as the incident beam. The light reflected from the beam
spreader is diverted so that it runs parallel to the incident beam. Those beams are reflected once more by
a mirror and onto the emulsion creating a reference beam.
•
•
When the reference and incident
beams strike the emulsion film, they
combine to form an interference
pattern. The interference causes
'fringe patterns' to be recorded onto
the film.
Incident
Beam
I
Fringe Patterns
I
I
I
I
I
I1• • • •
_
/
Holograms are the recordings of these fringe
patterns. If the incident beam and reference
Interference
Pattern
I
beam that strike the film are in phase then
I
I
the interference is
constructive and
light will be visible
at that poi nt on the
film. Conversely, if
~ Reference Beam
the reference and
incident beams are
180 degrees out of phase,
they cancel each other out. This is
destructive interference. There will be no
light visible on the film at those points.
I
I
I
I
In order to retrieve the information stored on the film coherent light
produced by a laser beam is shone through it. This new reference beam interacts with the pattern
left on the film; the fringe pattern. The diffraction occuring between the light and fringe pattern
combine to allow the image to be reconstructed. Though the object is no longer there, it can
still be seen on the film and appears to be 3D.
Ji;;~~\' - - - -
------
lis
for Inertia
Before Newton, people believed in the Aristotelian view.
Aristotle had different laws of motion for earth-bound objects and
celestial bodies. Essentially, Aristotle's law stated that in
the absence of forces, anything on earth will eventually
slow down and stop.
t
r
Newton's laws of motion are universal - they apply to all objects in
the entire universe. His first law states that an object in motion continues
to move at the same speed and the same direction unless acted upon by
another force. This is often called the law of inertia.
If a person is standing on a skateboard, then he will not move unless some
other force pushes or moves him. If a person is riding a skateboard down the
street and hits an object such as a curb, the person will continue to go in
the same direction and speed. Although the skateboard has stopped, the
person's motion continues in the same direction and same speed that it was
initially going.
/
Another example of inertia is when a space
shuttle takes off and is boosted into orbit
around the earth. Initially, astronauts fire up the
engines to gain the height and speed needed to
\ leave the earth's atmosphere. Once high enough,
the astronauts shut off the engines, and the space
\ shuttle stays in orbit because of inertia.
/
(
I
(
r
lin space, there is no air resistance but there is
still the affect of gravity. The combination of
inertia [which keeps the space shuttle moving at
/ a constant speed] and gravity cause the shuttle
to move in an unchanging circular path.
l
I
\
\
\
~
.
/
/
/
/
Both of these examples show how objects resist
changes to their motion - it is this resistance to
change that we commonly call inertia.
Newton's Second Law
Newton's second law states that the force applied to an object will produce a corresponding acceleration.
This acceleration is dependent on the mass of the object: a given force can move a large mass at a low
acceleration or a small mass at a large acceleration. This applies to individual objects as well: a large force
will move an object with a large acceleration, while a smaller force will cause it to move with a proportionally
smaller acceleration. The images below have the equation force equals mass times acceleration. If the mass
of the object is small, such as a golf ball, then the acceleration is greater. While a larger object, such as a
bowling ball, has less acceleration because of its greater mass.
IF=ma I
Momentum
A consequence of Newton's second law is
the concept of momentum. Momentum is
the product of an objects mass and velocity.
It is similar to inertia in that it helps to
quantify how long a force needs to act on
an object to speed it up or slow it down:
The way to solve for any of these is to use
the equation below.
p
== mv == Ft
p=momentum, m=mass, v=velocity, F=force, t=time
I.
I'
I
I'
h
~,~
~~
, , - / Newton's Third Law
Newton's third law states that for every action there is an equal and opposite reaction.
This explains that when one object applies a force on another object; the second object
puts a force of equal strength in the opposite direction on the first object.
For example, if a man fires a shotgun, once he shoots the gun he will feel the "kick"
from the force upon the shotgun which is equal to the magnitude to the force that
pushes the pellets. In the image to the left, the blue arrow represents the force applied
to the bullet being shot out of the shotgun and the red arrow shows the direction and
momentum in which the gun recoils through because of the force of the bullet exerts
on it.
The last force working in this example would be that of the bullet hitting the target.
In movies, when a person is hit by a bullet they are often thrown violently backwards.
Ifthis were to happen in reality, the person firing the gun would get an equally violent
"kick" from the recoil of the gun.
Jis for J.J. Thomson
J.J Thomson was born in 1856 in Manchester England. He was
alsocavendish professor of physics and had Ernest Rutherford
as his student. The Plum Pudding model resembled a round
positively charged sphere with negatively charged electrons
randomly placed throughout it. There was no concept of a
central nucleus in this model. This resembled an English plum
pudding with the static electrons in place of the plums.
Created by J.J. Thomson, the model was proposed to the public
in 1904. This was before the discovery of the atomic nucleus
and therefore was disproved when the atomic nucleus was
discovered.
The Rutherford model (below) was modeled like the modern solar
system, with the nucleus as the sun, and the electrons as
orbiting planets. This model is not in fact totally correct but
has some correct factors, like how there is a nucleus in the
Vacuum
center, how the electrons are surrounding the nucleus, and that
the electrons give an atom it's size.
The incorrect factors of this
model include not showing the
correct energy levels,
.-
@
allowing
the
electrons to orbit any
<±)
(i)
where and lastly that
'
the model could not explain
why the electrons did not spiral inward.
Rotateable
Mic oscape
Neil Bohr's model is a modification of the Rutherford model. In Bohr's model the electrons are described by
a wave function. Bohr thought that electrons could only go where a
whole number of wave lengths fit into the orbit. What is right
about Bohr's model is it explains why only certain orbits are
allowed, that it correctly predicts
Spectral line
energy levels and transitions,
Nucleus
and how it takes the
Rutherford model and
quantum
applies
mechanics to it. The only
real flaw in Bohr's model
is that it is too simple to
even describe something as
easy as hydrogen perfectly,
although it accurately describes the
n = 3
basic principles.
Electron Orbit
K is for kinetic energy
Kinetic energy is the energy that an object has because of its motion. The direction of the motion does
not matter; any object with motion has kinetic energy. Kinetic energy is equal to one-half the product
of an object's mass and the square of its velocity.
2
As an object falls, it accelerates and potential
energy is converted into kinetic energy. The potential energy becomes entirely kinetic energy
immediately before impact with the ground. At
each point of the object's descent, the sum of
the kinetic and potential energy is nearly
constant. However, some energy is lost while
the object heats up due to wind resistance.
Mass is measured in kilograms • Velocity is measured in meters per second • Kinetic energy is measured in Joules
-
A yo-yo would have its maximum potential energy when it is being
held in a person's hand above the floor. As it begins to unwind and fall,
the potential energy is gradually converted into kinetic energy.
Virtually all the potential energy is transformed into kinetic energy
once the yo-yo is spinning at the bottom of the string. As the yo-yo
travels up and down, it is repeatedly exchanging potential and kinetic
energy. In addition to linear kinetic energy, the yo-yo also has
rotational kinetic energy when it is spinning, similar to a flywheel.
The amount of kinetic energy one object can yield depends on v 2 • Because velocity is squared, an object
moving at 100 meters/second has one hundred times the kinetic energy than it would have if it was traveling
at 10 meters/second. A car moving at 60 miles per hour has four times the kinetic energy of a car moving at
30 miles per hour. Because kinetic energy quadruples as velocity doubles, accidents at high speeds become
incredibly dangerous! In a crash, energy is used to crush the car and a great amount of force is exerted on the
vehicle's occupants.
is for light
Light is a form of energy that is carried by electromagnetic waves. These waves are produced by the motion
of electrically charged particles. There are many examples of electromagnetic radiation - the name we give
each one depends on the frequency of the wave. Low frequency gives rise to radio waves while very high
frequencies create X-rays. The continuous range of frequencies is known as the electromagnetic spectrum,
and the narrow band that can be detected by the eye is called visible light. The wavelengths of visible light
are between roughly 380 nm and 740 nm. Wavelengths outside that spectrum cannot be seen by the human
eye.
t:~I~I~
600
Wavelength
500
400
A measured in nanometers (nm)
White Light
Monochromatic light is light of a single color and a single
wavelength. For example, monochromatic light at 500 nm
appears turquoise while monochromatic light at 600 nm is
yellow. White light consists of all the visible wavelengths
at once. When we pass white light through a triangular
prism, it separates into its component colors. The
separation of visible light occurs because light waves bend
by varying amounts depending on their wavelength. This is
known as dispersion.
---:::~~~• • •Red
Orange
Yellow
Green
Blue
Indigo
Violet
Glass Prism
Color Vision
The human eye and brain work together to translate light into color. Light receptors within the eye transmit
messages to the brain that produce the familiar sensations of color. Inside our eyes are cone cells that help
provide us with color vision: an S cone (short wavelength: blue color detection), an M cone (medium
wavelength: green color detection), and an L cone (long wavelength: red color detection). Red, green, and
blue are the additive primary colors of the color spectrum, and by carefully combining these colors, we can
create an optical illusion tricking the brain into thinking we are looking at colors that are not really there. For
instance, when we see yellow on a computer screen, we are not looking at 600nm yellow light. The color is
produced by the green and red region of the color spectrum. By varying the amount of red, green, and blue
light, all of the colors in the visible spectrum can be produced.
1.0
>.:;
7.5
+-'
:-e
Vl
0.5
c
OJ
V)
2.5
0.0
400
500
600
700
Infrared and Ultraviolet Light
There are many types of light that make up a band of radiation frequencies called the electromagnetic
spectrum. Every single type of electromagnetic radiation transfers energy through waves of oscillating
electromagnetic fields. We are able to classify each type of radiation by its frequency and wavelength. There
are five main types of radiation on the electromagnetic spectrum: radio, microwave, light (both invisible and
visible), x-ray, and gamma ray.
Infrared radiation (lR) and ultraviolet light (UV) are types
of light that are invisible to the naked eye. The reason we
cannot see infrared radiation is because its wavelength is
outside the range of human vision. Visible light ranges
from wavelengths of 380 nanometers to 750 nanometers.
The wavelength of infrared radiation ranges from 700
nanometers to 300 microns. Red has the longest
wavelength on the color spectrum, so infrared light is
sometimes referred to as "redder-than-red".
Infrared radiation is usually emitted by objects that
absorb and reflect heat. An example of this is when a
piece of aluminum foil is placed in the sunlight. Eventually,
you will be able to feel the heat energy radiating off of it.
It is also hot to the touch.
Infrared
Visible Ught
Ultraviolet
In the graph above, you can see the order of
wavelength from longest to shortest. The
three types of radiation shown are infrared
radiation, visible light, and ultraviolet
radiation.
Aluminum foil absorbs infrared radiation and reflects it. As an object's temperature increases greatly its
infrared radiation gets closer to becoming visible light. Infrared itself is not heat; the energy of the radiation
is what causes an object's heat to increase. Intense infrared radiation can damage or burn living cells, killing
them.
Thermal imaging cameras use infrared radiation. By using specially cooled ccd arrays, cameras can be made
that are very sensitive to low levels of heat. These cameras can be used for tracking people, night vision,
astronomy, and weather prediction amongst many other uses. Other forms of light can also be imaged in this
way: ultraviolet light imaging can show damage to skin and also to crops. Art historians often find surprises
when they look at ultraviolet, infrared, and x-ray images of art works.
Ultraviolet light, like infrared radiation, cannot be seen by the
human eye. Its wavelengths range from 10 nanometers to 400
nanometers. The name "ultraviolet" came from
its
electromagnetic waves that have frequencies that are higher
than the color violet.
Dentists use ultraviolet light to create a
chemical reaction in the paste used to fill
teeth. Once the paste comes in contact with
ultraviolet light, it hardens and creates an
invisible filling.
UV light can be found in sunlight. When you get sunburned, it is
because of UV light's effect on human skin. The UV radiation
mutates the DNA in our skin cells, causing them to die. Our body
then has to shed those skin cells and produce new ones. There
are two types of ultraviolet light. UVA is the longer wavelength
of ultraviolet light, and UVB is the shorter. UVA can lead to skin
cancer. UVB, the shorter wavelength of ultraviolet light, usually
just causes sunburn.
Lasers
Lasers have become a staple of the digital age. They are used in a variety of different things, from CD and
DVD readers, to cutting diamonds, to eye surgery. Yet not many people actually understand how they work.
There are several different types of lasers, but they all share some fundamental traits. All lasers work by first
causing the atoms of an "active medium" to enter an optically excited state. When an atom becomes
excited, one of its electrons absorbs extra energy, causing it to jump to a higher-energy orbit. Only
certain materials can be used as a medium, but the material can be a solid, liquid or gas. The
first lasers used a ruby crystal as a medium. Most lasers excite the atoms by
shining a bright light into the medium or sending pulses of electricity
into the medium. Electrons in a high-energy state
eventually wish to return to their ground
state, so at some point the
energized electrons hop back
down to ground state. For
a Ruby Crystal
b
Flash-tube
them to make this jump
c
Semi-reflective
Mirror
down, they have to
d Fully-reflective Mirror
release the energy
e Power Supply
they absorbed. To
f Laser Beam
release their energy, the
electrons emit photons (small
"packets" of light). The photon's wavelength, which dictates its color, is determined by the difference in
energy between the higher-level state and the lower-level one. When one of these photons reaches another
excited atom with an electron in the same higher-energy state, that atom in turn releases a photon of its
own. This reaction causes the number of photons to grow extremely quickly as more and more photons hit
excited atoms. Since the difference between the higher and lower-energy states is the same in all the photon
producing atoms, all the photons have the same wavelength and are in-step with each other, or "coherent".
This is why lasers produce beams of light that are a single color.
This process is called stimulated emission, and in order for it to work effectively there must be more excited
atoms in the medium than non-excited ones. We call this population inversion. The higher the number
excited atoms compared to non-excited atoms, the greater the degree of population inversion. The greater
the degree of population inversion, the more effectively stimulated emission works.
The coherence of photons and two mirrors at opposite ends of the lasing tube give lasers their signature
narrow, focused beam. A fully reflective mirror is placed at the back of the laser and a semi-reflective mirror
placed at the front. Some of the photons bounce off these mirrors, but only photons that travel parallel to
the lasing tube's horizontal axis remain inside the laser cavity. The semi-reflective mirror allows some of
these photons to pass through, while reflecting others back to the fully-reflective mirror so the stimulated
emission of photons in the tube continues. The photons that pass through the semi-reflective mirror are the
intense, narrow beam of light we see produced by the laser.
The technical term for this whole process is "light amplification by stimulated emission of radiation", or
"laser" for short.
Compact Discs
The first compact disc was made commercially available in
1982. Now billions are used worldwide every year. But how
do these revolutationary storage devices work?
A compact disc is composed of a thin layer of
aluminum sandwiched between two plastic ones.
laser pickup
pits
The aluminum layer in the middle of a compact disc is covered in microscopic pits. To retrieve information
stored on a compact disc, a low power laser beam is shined onto a semi-reflective mirror that reflects the
beam onto the surface of the disc. When the laser beam hits a flat part of the disc, the beam bounces back
through the semi-reflective mirror. This produces a flash of light that is read by a light sensor behind the
semi-reflective mirror. When the laser beam hits a pit, the beam is scattered and not reflected. The light
sensor reads the flashes of light as on-off signals. These on-off signals represent binary code, a system of
counting using only O's and l's.
standard
binary
10
9
8
7
6
5
4
3
2
1
o
0 1 0 1
100 1
0 0 0 1
1 110
0 1 1 0
1 0 1 0
0 0 1 0
1 100
0 1 0 0
1 0 0 0
0 0 0 0
Il-" 0"
the digits of
binary are
exponents
of two
~" ~"
o<::,~",o"::>rv<f
2° = 1
21 = 2
22 = 4
23 = 8
Each additional digits
place is equal to a
higher power of two
The digits places in binary are exponents of 2 in standard decimal form. So
the first digit is 2°, meaning a 1 there is equal to 1 std; the second digit is
2\ so a 1 there is equal to 2 std; the third digit is 2 2 , so a 1 there is equal to
4 std, and so on. To find the value of a binary number in standard decimal
form, add up all the standard decimal form values of the digits places in
the binary number where there is a 1. So 0 1 lOis equal to 0 + 2 + 4 + 0,
which equals 6 in standard decimal form.
These sequences of pits spiral around the disc outward from the center.
For the disc to be read properly, the laser must be kept in extremely
precise alignment with them. This means the laser has to move in
incredibly small increments to stay in sync with the disc. This is done using
a tracking motor that moves the laser microscopic distances. In addition,
the disc motor that rotates the CD changes the speed of rotation
depending on the track it's on. In other words, to keep the laser covering
the same amount of surface as it moves further away from the center of
the disc, the disc is spun at different speeds. The disc motor spins the disc
at speeds between 200 and 500 rotations per minute.
is for Magnetism
The History of Magnets
.N
The first application of the magnet was in its use in compasses. It was
observed that certain materials would align themselves to point north.
Because of this, the ends of magnets are now thought of as having north
and south ends. There is a magnetic field that surrounds the earth, and its
magnetic pull makes the needle of the compass, which is a magnet, turn to
magnetic north. What we think of as the north pole is actually the location
of a physical south magnetic pole; this is why a needle of a compass will
point north. Earth's magnetic field pulls towards north. Georgrahical north
is the axis that the earth is spinning on. The angle between magnetic north
and geographical north is called the declination.
s
Magnetic Fields
A magnetic field is the area surrounding a magnet where it produces a magnetic force. This is shown in the
first diagram below. Two like poles repel each other, and opposite poles attract. When a north and a south
end are put together, the field lines produced look like the second diagram below. When two
repeling ends are put together, the field lines push against each other. The field
Magnets are either
lines made by two opposing ends also produces a negative space where there is
"hard" or "soft"
no net force. This is shown by the X in the diagram below.
according to how
difficult they are to
magnetize and how
long they stay
magnetized.
Scientists believe
that the earth's
magnetic field will
completely reverse
every few hundred
thousand years.
Electromagnets
Electromagnets refer to the creation of a magnetic field when an electrical current flows. This reaction was
discovered by Oersted in 1918. If a wire is suspended above a compass that points north, the needle will
not move until an electrical current is put through the wire. If the current is reversed, the compass will
move in the opposite direction. This discovery was developed into
Soft Iron Core
.
. .
creating the electromagnet, which can be sWitched on and off
according to whether or not there is a current flowing through the
Coil
wire. The strength of the electromagnet will increase if any of the
following occur:
I. The current in the coil increases
II. The number ofturns in the coil increases
III. The poles are closer together
is for Nuclear
Chances are, if you're reading this book, you've already had a science class or two so likely you've come
across the term 'Nuclear' before. (Or perhaps you've even heard it pronounced as "Nu-QU-Iar"). But many
people throw the term around without really understanding what it means.
In chemistry, we learned that all things are made up of atoms, which are the basic building blocks of matter.
Atoms, as you probably know, are made of protons, neutrons, and electrons. Protons and neutrons form
what scientists call the nucleus. The term 'nuclear' merely refers to anything that involves a nucleus.
Nuclear reactions are changes that occur in the nuclei of atoms. These changes are important because they
often create new atoms. They also generate NUCLEAR ENERGY!
"But how do I know these reactions are really there?" you ask. Well, nuclear energy can be observed around
us all the time whether by natural means or human produced. After all, it's been around longer than
electricity or gasoline!
Human Produced Reactions:
Natural Reactions:
Nuclear power plants and reactors
are an alternative source of power
to gasoline, which is becoming much
harder to find. France gets over 75%
of its energy from nuclear power.
The sun and other stars
make heat and light
by nuclear reactions.
Fission, Fusion, and Spontaneous Nuclear Reactions!
Nuclear reactions are important because they generate nuclear energy, which can be utilized for a variety of
industrial purposes. The three most common types of nuclear reactions are fission, fusion, and spontaneous
reactions.
Fission
A process where a large
nucleus is split into two smaller
daughter nuclei. This creates
a substantial release of energy.
~E
Fusion
A note about
Spontaneous Reactions...
A process when two nuclei with
low mass numbers are joined to
form a singular heavier nucleus.
This also creates a substantial
release of energy.
/t's important to note here that all nuclear reactions do not occur from the processes
offission or fusion. Often, changes can occur without splitting or joining nuclei.
But how do nuclear reactions relate to the real world?
Currently nuclear power plants rely on fission reactions to
produce power. The Earth has limited supply of coal and oil.
Nuclear power plants could still provide energy once these
become scarce. They also need less fuel and produce more
energy. Nuclear energy has a variety of other applications
such as medical imaging,
detection, and many more.
The Big Question:
radioactive dating,
radiation
Fission based power plants rely
on rare uranium and plutonium
as fuel, which are extremely difficult
to extract.
"ls there any way to produce
nuclear power more efficiently?"
~
E
==
mc2
Einstein's Famous Equation
Energy is equal to the mass multiplied by the
speed of light squared. But what does this really
mean? In the case of nuclear reactions, since the
speed of light is a constant number, mass is the
only thing that can change the amount of energy
output in this equation. In reactions such as
fission, where a nucleus is being split, the
combined mass of all daughter nuclei (including
the free nuetrons) is slightly less than the mass of
the original nucleus. This mass deficit is a fraction
of the mass of a single nuetron or proton. Infusion
reactions, the nucleus created by the original
nuclei has a lighter mass than the original nuclei
had when their respective masses were added
together. Like fission reactions, this 'missing mass'
is the source of the energy release.
The Future of Nuclear Energy: FUSION POWER!
The "Hydrogen Bomb" is an explosive
based on the fusion of hydrogen. It
utilizes an uncontrolled fusion reaction.
Since the 1950s, scientists have been
attempting to develop a form of
~E
controlled fusion reactions and use the
technology
to
produce
electricity.
Hypothetically, the waste from fusion
power plants would be less toxic or
possibly not toxic at all. Also, fusion
power plants could utilize various
hydrogen isotopes as fuel that can be
extracted from the oceans as opposed to
uranium or plutonium.
Modern science is pressing forward with
various ways to overcome the obstacles
that stand in the way of fusion power.
The main roadblock lies in the fact that
the charges of hydrogen nuclei repel
each
other
because
they
are
both
positive. In order for fusion to take place,
two nuclei must touch. Currently, three
methods are being studied to achieve
this. The most promising method is
magnetic confinement, also known as
"The Tokamak Approach."
Scientists discovered that high temperatures are needed in order for
the nuclei to touch and fusion reactions to occur. Because heat is
generated by kinetic energy, this means that the nuclei must also move
very fast. The Tokamak was a device invented in the 1950s by Soviet
physicists that utilized an extremely powerful magnetic force in order
to contain the matter so it did not come into physical contact with the
walls. If the nuclei touched the walls, energy would be lost making it
impossible to initiate fusion.
Radiation
Radiation is a topic central to nuclear physics. An extremely broad topic, radiation generally
refers to any type of energy (such as light) that travels through space. Radiation itself is
divided into two types: non-ionizing and ionizing radiation.
Non-ionizing radiation is the type people are most familiar with, though usually by
other names. The term encompasses radio waves, microwaves, as well as visible
light.
•
lIIIIIia
Conversely, ionizing radiation is the type involved in nuclear reactions like radioactive decay and
fission. Ionizing radiation is capable of stripping electrons from an atom, turning it into an ions,
due to the amount of energy its waves contain. Consequently, ionizing radiation poses a
medical risk becaue if the molecules in your DNA are ionized, they will be damaged, and
your cells may mutate. That process is how this type of radiation causes cancer.
Isotopes
One cannot understand nuclear reactions, and consequently, ionizing radiation,
without learning about isotopes. The term isotope refers to the different forms of
a specific element. Specifica lIy, the nu m ber of protons determ ine the element of an
atom, the number of neutrons determine the isotope, and the number of electrons (compared to the number
of protons) determines the charge. Take for example, Hydrogen: its atomic structure consists of a single proton,
and anywhere from zero to a dozen neutrons. Any atom with one proton will be an atom of hydrogen, but the
different isotopes of it contain different numbers of neutrons.
Below are the isotopes for a few well known elements. Only a few are shown; Hydrogen has seven different isotopes, while Uranium has over thirty
Uranium
Hydrogen
lH - Protium
1 Proton
o Neutrons
The most common isotope of hydrogen, making up
99.98% of hydrogen on Earth. It is a stable isotope.
2H - Deuterium
1 Proton
1 Neutron
The second most common isotope of hydrogen, making
up <.02% of hydrogen on Earth. It is a stable isotope.
3H - Tritium
1 Proton
2 Neutrons
The least common isotope of hydrogen, found only in
trace amounts on Earth. It is unstable, and undergoes
beta minus decay with a half life of "'12 years.
235
.
Uranium
238Uranium
239Uranium
92 Protons
143 Neutrons
92 Protons
146 Neutrons
92 Protons
147 Neutrons
The second most
common isotope
of uranium. Undergoes Alpha
Decay and has a
half-life of 7.10 8
years.
The most common
isotope of Uranium
found on Earth. It
Undergoes Alpha
decay and has a
half-life of roughly
4.5.104 years.
Naturally found
only in trace
amounts. Undergoes Beta decay;
has a half-life of
24 minutes.
Stability, Decay and Emitters
An atom's stability is dependant on the various forces at work within them. These forces are determined by the
number of protons and neutrons, and the ratio between the two. As a result, different isotopes of the same element can undergo different types of decay. In Hydrogen we see that protium PH) is a stable atom with 1 proton
and 0 neutrons, whereas tritium is unstable with 1 proton and 2 neutrons. In order to reach stable states, atoms
like tritium undergo decay.
There are three types of radioactive decay, known as Alpha decay, Beta decay, and Gamma decay. Each type of
decay is a different, but all types bring atoms towards a more stable
ex Decay
state. Atoms that perform these types of decay are
called emitters, because during radioactive decay,
they emit particles. Those particles vary depending
rx Particle
on the types of decay the atoms undergo. The emit+
ted particles travel in "waves", named after the type
of decay that produces them.
4Helium
[2 Protons, 2 Neutrons]
Alpha Decay
Alpha decay frequently occurs in larger atoms with
too many protons relative to their number of
neutrons. During Alpha decay, the atom emits a 4He
(Helium-4) atom, called an alpha particle. The atom
loses two protons in this emission, subsequently
becoming a different element. Alpha waves are
frequently stopped by air, due to the size of their
particles.
Beta Decay
Beta decay occurs in a nuclei with either too many
neutrons or too many protons. There are two types:
Beta minus and Beta plus. Beta minus transforms a
neutron into a proton, and emits and electron and an
anti-neutrino. Beta plus transforms a proton into a
neutron, and emites a positron (an anti-electron) and
a neutrino. Beta Waves travel through air but are
stopped by materials like plastic, as well as human
flesh.
Gamma Decay
238Uranium
234Thorium
[92 Protons, 146 Neutrons]
[90 Protons, 144 Neutrons]
~-
Decay
~
-+
+
3Hydrogen
3Helium
[1 Proton, 2 Neutrons]
[2 Protons, 1 Neutron]
Particles
•
Electron
•
Anti-Neutrino
~+ Decay
~
Particles
Positron
+ o Neutrino
llCarbon
llBoron
[6 Protons, 5 Neutron]
[5 Protons, 6 Neutrons]
Gamma decay is unique in that it simply involves an
atom 'descending' from a higher energy level to a
lower one. In Gamma decay, an atom maintains all its
protons and neutrons. However, it emits energy in the form of dense packets of light called "photons". :.:.:.:~
Gamma waves travel through air, flesh, and even
,lead. Of the three types of ionizing radiation, gamma
I I) \
waves are the most dangerous because of that fact;
Energized
they are the most likely to interact with your DNA.
y Decay
y Particle
+
\\
'.
3Helium
[2 Protons, 1 Neutron]
3Helium
[2 Proton, 1 Neutron)
Photon
Carbon-14
Carbon-14 is a carbon isotope. A normal carbon atom has a nucleus that consists of 6 protons and 6
neutrons. An isotope is an atom that has a different atomic mass than the usual atom. In this case, the
atomic mass is 14. The carbon-14 nucleus contains 8 neutrons instead of 6 neutrons, and this makes the
isotope radioactive.
Creation of C-14
Neutron - .
Proton -
How is C-14 made
and put into the environment?
ln +14N -714 C + lH
Carbon-14 is made at very high altitudes
(9-15 km). Neutrons playa vital role in C-14
creation. Extremely high energy cosmic
rays from outer space collide with gas molecules in the upper atmosphere. Occasionally, this causes a neutron to be ejected.
Sometimes, this neutron collides with a
nitrogen atom. Once the nitrogen is hit, a
proton is released while the neutron is
absorbed, forming Carbon-14.
,{ Cosmic rays collide with
"/ Nitrogen in the upper troposphere
Neutrons make up approximately
90% of cosmic rays
H d
~
/v.
.---i~~
yrogen
The neutron knocks a
proton out of the Nitrogen
Which makes C-14 isotopes
Carbon Dioxide can be
absorbed in by trees and
other plants
Radioactive Dating
Plants are
eaten by herbivores
One unique use of C-14 is radioactive
dating. Carbon-14 dating requires a basic
knowledge of radioactive decay. Radioactive material, such as Carbon-14, decays
at a rate called a half-life. A half-life is
measured in a specific amount of time.
Each radioactive material has its own
unique half life.
Humans eat both
plants and animals
~
~
~
In one half life, an organism gives off half of the radioactive material. For Carbon-14, the half life is
approximately 5,700 years. This means that it takes a non-living organism about 5,700 years to give off
half the amount of the C-14 it has. Below is an example of a Pterodactyl. The amount of Carbon-14 fluctuates throughout its life, but decays once it's dead.
Rate of C-14 Deca
C-14 Amount -
1/1
~
1
7
0
M
LLION
YEARS
o
PRESENT
®jS for Optics
Optics refers to how light propogates through different types of matter. Optics has been studied since the Egyptians created lenses from a polished crystal. The study of optics continued with the Romans as they filled glass
vases with water to create lenses. Now optics includes the use of lenses, mirrors, prisms, and fiber optics.
Convex Lens
Concave Lens
The convex lens is often used to look more closely at The concave lens is often used to make larger objects
smaller objects, such as coins or stamps. Seen above is seem smaller. Seen above is a double concave lens.
a double convex lens. After entering the lens, the light After entering the lens, rays of light bend outward, or
rays bend inward, or refract, focusing the light on one diverge, spreading the light outwards. Note how the
point. Note how the light rays that enter farther away light rays that enter farther away from the axis bend
from the axis bend inwards more. As seen in the outwards more. As seen the in the diagram below, a
diagram below, a convex lens makes the lightbulb concave lens makes the lightbulb appear smaller when
appear larger when projected onto a screen. Convex seen. Concave lenses are used to correct near-sighted
lenses are used to correct far-sighted vision.
vision.
-Object
-
Object
Projected Image
I_:-/-::-/---+ v ---+11
Virtual Image
I+--v----+
•
1+---- U
The Telescope
Telescopes allow an object
to appear larger without inverting the image. To measure the
amount of magnification in a
telescope, divide the distance from
the center of the objective lens to the
focal point, F0, by the distance from the focal
length to the eyepiece, Fe .
-
1
I
•
---~I
Thin Lens Equation
The thin lens equation is used to
determine at what distance rays of
light will intersect after going
through a I ns. This equation is
able to ca
late the size and type
of the pres ription gl~ses you need.
The distance from the obJ ~the~~s is u. The
distance from the object to t~ . Ji?~cfel(image
is v. The focal length of th, I~ . is f~~onvex
lens has a positive focal
concave lens
has a negative focalleng
;':/;'I.t
u
I
Mirrors
If\J! llOl2 \
Concave Mirrors are
used to direct light. An
ideal shape of a concave
mirror is a parabola,
which causes all of the
light rays produced by
the bulb to go in one
direction.
Concave
mirrors can be seen in
flashlights and car headlights.
Mirrors are surfaces that reflect light. The most familiar mirror is called the
plane mirror, which is a mirror that is completely flat. Mirrors that are
curved can diminish or distort images, as seen in fun houses. Mirrors are
used in everything from bathrooms to cameras to industrial machinery.
Convex Mirrors are used
to spread light. The ideal
shape of the convex
mirror is a a half of a
sphere, which causes all
of the light rays produced
by the bulb to go in all
different
directions.
Convex mirrors can be
seen in rear-view mirrors
in vehicles.
Mirrors that are
angled can also
be used to redirect light and
images, as seen
in a periscope.
Notice how the
orientation
of
the image is kept
the same after it
has been passed
through
two
mirrors. Had only
\I--I-l-----l
one mirror been
used, the image
would have been
seen as a "mirror
image."
Above is an example of how prisms can be used. The image
is flipped downwards (vertically) then across (horizontally).
Once the image has gone through both prisms, the
processed image is an exact opposite of the actual image.
Binoculars are very much like telescopes. However,
telescopes require a lot of length to be effective. Binoculars
are able to be short because prisms force the image to travel
the shorter distance multiple times. As seen above, the tree
image travels the same distance three times because of the
prisms.
Fiber Optics
Fiber optics were hailed as the future of communications
cablesduringthe 1990s. Offeringan extremelyhigh bandwidth,
fiber optics have gradually replaced the more commonplace coaxial cable. Now,
they're found in various communications networks. Although coaxial cables can
carry high bandwidth signals, these signals are lost easily over long distances. When
transferring high bandwidth data over long distances (for instance, from Los Angeles to
New York), fiber optic cables are preferable.
Fiber optic cables, which transfer data with light, require amplifiers for longer transmission
distances. In past long-haul systems, the light signal had to be converted into an electrical signal
before amplification could happen. Recently, strides towards all-optic systems have been made
such as using semiconductor optical amplifiers (SOAs) or eridium doped fiber amplifiers (EDFAs).
These amplifiers can boost the signal strength while keeping it in its optical form, making it
unnecessary to occasionally convert from optical to electrical and back.
Total internal reflection is what allows light to travel
through the fiber. When light passes from one medium
into another medium that has a lower index of refraction, the
light will bend away (the green line in the diagram at the
right) from an imaginary line that is perpendicular to
.
the line between the two media (the orange in the ~XI~
diagram on the right). At a certain angle, known as the
critical angle, instead of refracting, the light will instead travel
along the surface between the two media (the blue line in the
Cladding
diagram on the right). At an angle greater than the critical angle, light
is reflected instead of refracted (the red line in the diagram on the right),
and travels through fiber optic cable by being reflected back and forth. In the cable, the cladding absorbs no
light from the core, so light can travel great distances. Light is really only lost due to impurities in the glass,
so optic cables cause much less signal loss per kilometer.
TAT-12 and TAT-13 were the first transatlantic fiber optic cables and were in operation from 1996 to 2008.
They were notable for the use of a self-healing ring structure. If a problem is detected, traffic within the
system can be redirected around the problem in less than 300 milliseconds--this is why the structure is called
"self-healing." In order to lay fiber optic cables down along the ocean floor, large ships that can support the
weight of the large spools of cable are needed. The cable on these spools are usually around 69 millimeters
in diameter and weigh around 10 kilograms per meter of cable. This weight and
diameter is caused
layers of
by the necessity to protect the cables from underwater conditions. There are several
sheathing used in the underwater cables such as the copper or aluminum tubing
aluminum
water barriers.
P
is for potential energy
Potential energy, specifically gravitational potential energy,
is defined as the energy stored by an object because of its
position. When held at a low height from the ground, the
potential energy is low. When held at a higher height from
the ground, the potential energy increases. This occurs
because of the equation:
PotentialEnergy = mass x gravity x height
Potential Energy Equation Explained ...
Potential Energy in Action ...
Potential Energy is equivalent to Work
Mass is measured in kilograms
Gravity is measured in meters per second squared
Height is measured in meters
In this example, the red
rubber ball, held above the
ground, has stored potential
energy.
The equation including the product of mass,
gravity, and height was derived from a series
of known equations. Beginning with the
equation of force:
Force = mass x acceleration
2.
We know gravity, which is measured in meters
per second squared, is acceleration, therefore:
When the ball is dropped,
potential energy is gradually
converted to kinetic energy as
the velocity increases.
Force = mass x gravity
The equation for Work is:
War k = Force x distance
By isolating force in the work equation, we'll
notice:
Force = Work -7- distance
3.
Then by setting the two force equations equal
to each other:
mass x gravity = Work -7- distance
We can replace distance with height because it
is the distance:
mass x gravity = Work -7- height
After rearranging the equation, the potential
energy equation is complete:
Work = mass x gravity x height
W=mgh
Did you know...
There is no actual zero point of potential energy. It seems
logical to believe that when the item is on the ground its
potential energy is zero but it's still possible to dig deeper
into the ground, thus allowing a negative potential energy.
Elastic Potential Energy...
The potential energy of a manipulated elastic object is known as
elastic potential energy:
ElasticPotentialEnergy
1
=
2,kx 2
The constant of the spring is defined by k. The stretch or compression relative to its dormant position is defined by x. Hooke's
Law is used to determine the force required to compress or
stretch a spring:
A spring is a good example of potential energy. Once
pulled apart, there is a force that resists the pull by
compressing the spring. The longer it is stretched,
the more elastic potential energy it has.
F=kx
Potential Energy Examples...
If a 1 kilogram ball is dropped from the top of a 6 meter
building, how much potential energy does the ball have
halfway to the ground?
PE
=
mass x gravity x height
PE
m
lkg x 9.82" x 3m
=
s
PE
29.4kgm
=
2
6 meters
s
PE
=
29.4J
When the 1 kilogram ball hits the ground, it compresses
.027 m. What is the force of the constant of the ball?
F
=
spring constant x spring displacement
F
=
mass x gravity
F
=
m
lkg x 9.82"
s
F
9.8N
=
=
9.8N
spring constant x spring displacement
9.8N
=
spring constant x .027m
.
sprzng constant
=
N
362.963m
is for Quantum Mechanics
History
Quantum mechanics is a branch of science that studies the behavior of matter and energy at the atomic
and sub-atomic level. Quantum mechanics attempts to quantify specific properties, such as position and
momentum, of particles (atoms, electrons, neutrons, etc.) These microscopic entities behave differently
than normal everyday objects because they exhibit the properties of both a wave and a particle.
Quantum mechanics describes these objects mathematically but is not descriptive about the mechanics
involved.
Light is one example of particle-wave duality. In the past, the true nature of light
was always a mystery. Was it a particle or a wave? Today, scientists have realized
that light shows particle or wave type characteristics depending on the
experiment. In 1905, Albert Einstein explained the photoelectric effect. He found
that photons (the particles that make up light) of a certain energy level release
electrons from negatively charged metals. Because the amount of electrons
A nucleus model of a
released from the metal depends on the energy contained in single photons,
nitrogen atom
Einstein determined that light was particle-like. Einstein believed this to be true
because red light could not release any electrons from negatively
charged metals while blue light could. He reasoned that wheter
electrons were released or not came down to the frequency of the
light. Higher frequencies of light have photons that contain more
individual energy than photons of lower frequencies. Only the high
frequency photons have enough energy to free an electron.
At around the same time that Einstein explained the photoelectric
effect, Neils Bohr was creating a model for electron orbitals around
a nucleus. He claimed the movement of matter at the subatomic
level was instantaneous and not continuous. In classical physics,
the electron is described as continuously accelerating in a curved path
towards the nucleus, losing energy while doing so, and thus releasing photons in the process.
However, if this were true then the electron would eventually accelerate right
into the nucleus. This obviously does not happen. Electrons do not run into
their nuclei. Instead, quantum mechanics describes the subatomic
transfer of energy much differently from that of classical physics. In this
explanation, energy is believed to exist in very small discrete units
called quanta. Energy can only be transferred in whole values of those
quanta units, so when an electron moves into a lower energy state, it
"teleports" into that specific orbital. There is no continuous
movement of that electron because it all happens instantaneously.
Bohr's radical claim stated that electrons could only exist in those
specific orbitals and nowhere in between.
The Copenhagen Interpretation
Neils Bohr most famous contribution to quantum mechanics was his Copenhagen
Interpretation. He claimed that all activity at the quantum level can be described by waves. In
fact, he claimed that anything at the quantum level does not physically exist. Everything is a
wave of probability, a probablity of existing at a certain spot in space. Only when a
measurement is made on the particle does the wave "collapse" and thus forces the particle to
reveal itself.
Schrodinger's Cat
In 1835, Edwin Schrodinger developed his famous thought
experiment known as Schrodinger's Cat. In the experiment, he
placed his theoretical cat in a box accompanied by a bit of
radioactive material and a Geiger counter. A Geiger counter is a
measuring device used for detecting radiation. The counter was
rigged so that if it detected radiation it
would trigger a hammer to break a flask of
poison and thus kill the cat. The radioactive
material had a 50/50 chance of decaying
after an hour.
Schrodinger's thought experiment emphasized the unbelievable nature
Copenhagen Interpretation was correct, then the cat should be both
obviously does not make sense. How can a cat be both alive and
collapse the wave function, meaning that the wave function of the
state to be, either dead or alive. Schrodinger was trying to highlight
make sense. Shouldn't the cat have been alive or dead before an
room? What qualifies as a conscious observer? He brought up
further prove how physics at the quantum level disagrees with
scale.
These notions got scientists like Bohr and Einstein arguing over
the true nature of the subatomic world. Bohr challenged our
understanding of reality by stating that subatomic particles
truly did exist as waves of probabilities. Einstein protested
against that with his famous quote: "Quantum mechanics
is certainly imposing. But an inner voice tells me that it is
not yet the real thing... I, at any rate, am convinced that
He does not throw dice." Einstein's life was devoted
towards trying to unify quantum theory and general
relativity. He did not succeed and quantum
theory's erratic nature, to this day, seems to
conflict with our understanding of reality.
of quantum mechanics. If the
partially alive and dead. This
dead? An observer should
cat would "choose" which
the fact that this does not
observer came into the
these profound questions to
physics at a much greater
«~
K is for Radio
Radio is a simple technology that is present in everyday life. From cell phones to baby
monitors to satellite communications, radios come in many different forms. Radio
signals are made up of two superimposed waves: A high frequency carrier wave plus a lower frequency
wave which carries the information being sent. Regular sound waves travel by vibrating air molecules
but these waves never travel far because the energy quickly disperses. Radio waves are electromagnetic
disturbances that can pass through buildings, around mountains, and even through space. By using
electromagnetic radiation we can carry audio waves over vastly increased distances.
AM &FM
AM- Amplitude Modulation
FM- Frequency Modulation
AM refers to a way of encoding information onto radio
frequency (RF) waves. The amplitude of the radio frequency
wave changes to match the audio signal. It is the simplest
way of encoding information and also the easiest to decode.
Unfortunately, interference is a very common problem. This
can be caused by anything from a car starting to noise from
electric appliances. Consequently, AM radio typically has a
lot of static.
FM is another type of radio transmission. In FM, the frequency
of the carrier wave changes with the audio signal. Typically,
FM has little interference and static noise does not alter the
radio wave frequency as much as it alters the amplitude. This
means FM has better sound reproduction in comparison to AM.
FM radio is also broadcast on a higher frequency carrier wave
which allows more information to be encoded. This means a
stereo signal can be sent over FM.
Amplitude Modulation
((( )))
Amplitude Modulated Wave
Recorded. Sound
Transmitter
The sound recorded from the microphone has two parts; the audio signal, which is the
actual sound, and the radio frequency, or carrier wave. Together, the two produce an
amplitude modulated wave that can be transmitted. The RF signal is the audio signal and
the amplitude of the signal changes in relation to the sound being produced.
Baby Monitors
Modulation Type: AM
Modulation Frequency: 49 MHz
Transmitter power: 1/4 watt
Oh no! Baby has woken up and cries out to
her Mommy and Daddy. Luckily they set up a
monitor in Baby's room. Now they are able to
hear her cries through the receiver with them in
the kitchen.
A baby monitor is a simple type of radio, so it has a transmitter and a receiver. Once the audio has
been encoded on the carrier waves the RF signal is amplified and passed over to the transmitting
antenna. The electrons in the antenna move up and down in relation to the signal creating an
electro magnetic field. This electromagnetic field radiates outwards from the antenna carrying the
radio signal with it. When it gets to the receiver it causes the electrons in the antenna to move in
the same manner. This creates a tiny electrical signal. The signal has a signature frequency. The
tuning electronics on the receiver filter out anything other than this frequency and decodes the
audio frequency. A baby monitor with a small power supply can typically transmit information up to
200 ft. A radio station typically uses 50-100 watts to transmit information for miles. A larger power
source allows the transmitter to send information further. The specific frequency also effects the
distance the information can be sent.
CDMA- Code Division Multiple Access
CDMA is a more complex form of radio that is commonly used in modern wireless
technologies, such as cell phones. Instead of assigning each user a specific frequency
per wireless device, CDMA uses multiple and varied frequencies to transmit the audio
signals. The reason for doing this is if one frequency drops out or becomes crammed, the
connection is not completely lost. All of the 3G technologies today are were created from
CDMA. During World War II, CDMA was used by the English so the German's could not
jam their transmissions and decode their messages. Now, Qualcomm commercialized
the technology and holds all patents.
is for Solar
SOLAR ENERGY
The sun is a star at the center of our
solar system. It accounts for
99.9% of the entire solar
systems mass. In the form of
sunlight, the suns energy
supports almost all life on
Earth. The sun is largely
responsible for the weather
and climate on earth as well.
Essentially, almost all energy
.
.:.
. .
•
Solar energy is the radiant light
and heat that the sun emits.
Humans have been harnessing
energy from the sun since
ancient times. The sun radiates
an immense amount of energy.
On a sunny day, the sun shines
approximately 1,000 watts
of solar energy per square
meter of the Earths Surface.
From the surface of the sun,
solar energy takes about 8
minutes, traveling 186,000
miles to per second, to reach
the Earth.
.
on earth leads back to the
sun. For example, for humans
to stay alive, they need to
consume food. That food would
not have been able to grow if it had
not been exposed to sunlight.
Plants use
photosynthesis by first
trapping light through their
leaves. They then convert that
sunlight into energy that they
use to create food for themselves.
~
SOLAR PANELS
~~
0( - - - - - - - - ,
The world currrently extracts a lot of energy from limited
I
natural resources. In an effort to move away from this,
~ ,ollIIIIII-"~
Battery
scientists are exploring the idea that the earth could ~:me day
Inverter
Or
System
run on free electricity from the sun. Photovoltalc Cells
19'
Produces DC
are an important part of this "solar revolution" because they
Converts DC power to
AC (alternating current)
(direct current)
Power
able to absorb light from the sun through semiconductors which
Power
convert sunlight into energy.
I
SEMICONDUCTORS
o
g
.-
The semiconductor is split into two sides. Both
are made of silicon but the pink side is infused
with Boron (the p-type layer), and the blue is
infused with phosphorous (the n-type layer).
Sunlight hits the p-type layer and knocks
electons from the atoms inside, leaving a hole
on the atom and giving it a positive charge.
The loose electrons are now inside the n-type
layer but are attracted to the p-type layer,
because of the positively charged atoms there.
They are then forced to complete a circuit,
which provides energy to the load that the
circuit is connected to.
is for superconductors
Superconductors are materials that conduct electricity without
resistance or loss. This means that an electrical current can flow in
a loop of superconducting wire, making it the closest thing to a
perpetual motion machine that can occur. Superconductivity is referred to as a
"macroscopic quantum phenomenon". This is a process that occurs due to the
quantum nature of atoms. We can see the effect on a macroscopic level, that
means we can see the effect with the naked eye.
~ij
fEI
L/,
3
The electrical resistance of an element increases along the T line. As the
element warms up, the atoms in the element get more excited and bounce
around. This bouncing makes it more difficult to conduct electricity. When an
element reaches its superconducting critical temperature, its resistance
3
C011 d
uetor
immediately drops to zero. When we look at the T line we can see that
resistance would eventually reach zero, at the zero Kelvin mark.
Superconductive materials will reach zero resistivity at a certain temperature.
The graph shows that this example reaches zero resistivity at 0.6 Kelvin. Different materials
have different superconductive temperatures.
Some materials, like wood, are not affected by magnetic fields.
ResiS1:ance
Other materials, like ferrous metals, when
exposed to a magnetic field create a field
.8
aligned with the original field. These
.6
paramagnetic materials absorb the field
and become magnetized themselves. If a piece of
.If
iron gets close to a magnet the field it creates
causes an attractive force. We see this effect as
t
.2
~~
# #
.5
T"""""'"""'
d~::.:,~ta I StiCkingGto
the ~iZ~'
1
r
When a magnet gets close to a superconductor its
magnetic field induces a current in the
~l~
superconductor. This induced current causes a
__..~
magnetic field to be created, which is a perfect mirror of the
magnet's field. This is called the Meissner Effect. The consequence of
this is that the two fields repel. When a superconductor is placed above a permanent
magnet this repelling causes the superconductor to "0
..
float. Continued research into superconductors
TetnPer~.,.
could lead to materials with very high
v~Ure
r0St-Crltlcal
~
temperature conducting materials \ \
~
~~
can. be. used in man~
different
OfA in CI
) )1)re-Crltlca\
applications. A potential use for
JI
r
superconducting critical temperatures. These hight (
~:;~e:~~~~~~~~a~~t~~:t~~~~:a~:v:
magnetic
tracks. The Meisner Effect could allow the train
to levitate without using huge amounts of power.
e
.
leroperature
~~
__
Tis for Thermodynamics
Thermodynamics is the study of the relationship between heat and mechanical
energy (a type of work), and the process by which one transforms into the other.
The laws that are associated with thermodynamics allow us to understand the
properties of heat-work interaction.
KE
I<E
.;- - -0+
f."
•.. ......
0-.
,
...... .•.. KE
""'~-~~~'"::r.I;;~"<:''"''''''''
'~~ ~~
-.~
. ~...
Yo'.
:.... ~::~~
~ •••...,..4 ')
KE, . ' ..h ' · ·
IJ:Y\-. KE
~
KE
@)+
..
~
~"I
'''_~' .•
_
"'~:~<~~''\''''Vit..
t~~~~,.', ~ _
~
"
. .~-'.'. "., " ....... : ;(~~".~-
~
-,r'
,...~"1"'~_...
, .. _. ~_:";:'j.'." ~:~~,;~~
-
.
,
<-~.~~
••
~.....
.., :~'-'~'~':'<;'l; -.;.::.
:;~~r(~~~··~~~
;· ......-....
..::..:;.;.'>.,.;'1i, ••.
"'''~'
.~~"
",~.;, .....~'''=''.:~':'.;:-
When kinetic energy (KE) is transferred into heat, we can
think of this process as coherent, regular motion as
being randomized. The molecular energy changes from a
neat, "ordered" system (with all molecules moving in the
same direction) to being "disordered". In physics, this
disorder can be measured and is called entropy.
Ludwig Boltzmann was an Austrian physicist who worked in the fields of statistical thermodynamics and
mechanics. However, long before Boltzmann a German physicist named Rudolf Clausius originated the
concept of entropy. During the 1850's-60's Clausius questioned the way in which heat could be used
when work is done.
,...-------....., Here, NS represents entropy, Q represents the amount of heat absorbed by a system
in an isothermal and reversible process in which the system goes from one state to
another, and T is the absolute temperature at which the process is occurring. All in
all, this equation represents the overall change in entropy based on the temperature
' - - - - - - - - - - ' of the system.
NS
Q
T
Isothermal and Adiabetic Processes
An isothermal process is a change in which the temperature of a system stays constant. This typically
occurs when a system is in contact with an outside thermal reservoir (heat bath), and the change occurs
slowly enough to allow the system to continually adjust to the temperature of the reservoir through heat
exchange. When a system exchanges no heat with its surroundings (Q = zero) the process is considered
adiabetic. This typically occurs as an explosion, and happens very quickly while an isothermal process
takes longer.
Reversible Process
In thermodynamics, a reversible process (or reversible cycle if the process is cyclic) is a process that can
be "reversed" by means of changes in some property of the system without loss of energy. Due to these
changes, the system is at rest throughout the entire process. Since it would take an infinite amount of
time for the process to finish, perfectly reversible processes are impossible. In a reversible process, the
system and its surroundings will be exactly the same after each cycle.
Absolute Temperature
Thermodynamic temperature is the absolute measure of temperature and is one of the principal aspects
of thermodynamics. Thermodynamic temperature is an absolute scale, because it is the measure of the
most important property underlying temperature: its null or zero point: absolute zero. Absolute zero is
the temperature at which the particle constituents of matter have minimal motion and can be no colder.
Note that this portion ties into the concept of absolute zero.
The Laws of Thermodynamics
Zeroth Law
When two objects are in contact with each other, they eventually reach equilibrium in
their temperatures
First Law
Energy can only change in forms, it cannot be created or destroyed, only transferred
Second Law
Entropy increases to reach thermodynamic equilibrium when isolation between two
systems is broken, allowing them to exchange energy. There is no energy as heat without a temperature difference
Third Law
Absolute zero (zero Kelvin) can never be achieved
Q-Te
This equation shows the change in entropy as a result of temperature. Here, Q
represents change. T(h) represents the hot temperature and T(c) represents the
cold temperature. The first term will always be bigger than the second. This means
that entropy is always increasing. Entropy can only decrease as a result of a manmade force. Even then, the small or medium increase in entropy is still not larger
than the increase in entropy. The entropy of a single object can go up or down, it
is the entropy of the universe that is always increasing!
Examples of Entropy
An air conditioner cools the air in a room, reducing the
entropy of the air. However, the heat expelled by the
air conditioning will always make a bigger contribution
to the entropy of the environment than the decrease
of the entropy of the air (heat must be expelled in
order to produce cold). So, even though the entropy of
the air is experiencing a slight decrease in entropy, the
increase is still larger in universal terms.
Disorder can also increase without heat flow! Atoms are
bouncing around inside a tied-off balloon. If you pop the
balloon, the atoms are no longer confined to a region, but
spread throughout the atmosphere.
is for Ultrasound
Sound Waves: High and low pressure pulses traveling through a medium that can pass
through solids, liquids and gasses.
High pressure
Low pressure
---+
---+
compression = particles are squeezed together
rarefaction = particles are spread apart
~
~
./
rarefaction
"
compression
Frequency: The number of pulses transmitted every second.
P/\f\f\f\/\
V\JVVvV
High frequency
fL\L\L\
V
V
V
V
Low frequency
Wavelength: The distance
the wave travels between
pulses.
Wave Equation: Calculates the velocity of a sound wave.
V==f·A
v= velocity
f= frequency
A.=wavelength
Humans can hear from 20 Hz to 20,000
Hz. Ultrasound operates at frequency
one thousand times greater than this.
Ultrasound: High frequency sound waves ranging from 1 MHz
to 20MHz with wavelengths of 1 to 2 millimeters.
.. :'
.
---=)0'
--" .- ~
./
...,
;:
"
•
..
"
The speaker is emitting sound waves, which bounce off the
object creating an echo, which can be analyzed so one can
identify the object.
When the sound waves encounter a
border between two tissues (stomach
and fetus) the sound waves bounce off
and create and echo which is analyzed
by a computer and transformed into
moving pictures.
Interal Rectus Muscle
is for Visif)ll
Lens
Vitreous
Body
The human eye allows us to see our surroundings by
Sclera
collecting light and converting it to electrical signals that are
passed to the brain. The outer layers of the eye comprise the Pupil-i/t-of---,..... I
cornea which provides most of the focusing for the eye and Iris
the pupil which limits the amount of light entering the eye.
Our eyes work differently from a camera where the glass lens Conjunctrua
moves forwards and backwards to focus an image. The lens
inside the eye remains at a fixed distance and instead changes shape Ciliary
in order to focus. The lens is linked to two muscles called ciliary Body
Medial Rectus Muscle
muscles. These stretch or compress the lens depending on the distance to the object. A thinner lens
focuses on distant objects, a fatter lens on things that are closer. Another important part of the eye is the
retina, where a focused image is converted to electrical signals. The retina is made up of 120 million rods
and 6 million cones that assist in adjusting in the dark or taking in as much light in order to see certain
objects and colors. These rods and cones are connected to more than 1 million neural pathways that collect
together to form what we know as the optic nerve. Since the human eyes are 2 inches apart, this gives
them two different views on their surroundings. This is called Binocular Vision. The brain is able to
interpret the two slightly different viewpoints and gain a sense of depth and distance.
View-Masters use binocular vision to create a three dimensional image. Once the
eyes are placed over the two holes each eye sees an image of a scene taken from
a slightly different viewpoint, just as our eyes would see if we were really
there. Using two such images to provide stereoscopic pictures is not new the technique was first used in 1840, and was common in Victorian times.
Birds can have Binocular Vision and Monocular
Vision - eyes on the side of their heads view a single
side each, but the visual fields overlap directly in front
of the bird. The binocular vision allows birds to judge
depth and distance of their prey, while the monocular vision to the side gives a wide
angle of view. This allows the birds to spot predators and prey easily. Hawks have around 1
million visual cells that cover each square millimeter of their fovea. This generates a crisp, un-blurred image
of a small object. Owls have eyes set on the front of their heads, therefore giving them stereoscopic vision
that helps judge distance. The only difference between these eyes and the hawks is that owls don't contain
as many rods. So they are to an extent, color blind.
3D Viewing tricks the mind into producing two different images, which
creates the illusion of three dimensions. One eye sees a red version of the
image, and one sees either a blue or green version of the image. Humans
have binocular vision, which means the brain will merge the two versions
of the image to create one 3D perception. However, because of the color
filters, 3D film lacks the quality of 2D color film and pictures.
Energy & Power
The Joule & the Calorie
Energy is defined as the ability to do work, whereas
Power is the rate at which work is done:
The Joule is the basic measurement of energy.
1 Joule is approximately the energy needed to
raise a small apple 1 meter. A Calorie is also a
unit of energy.
Power
Energy
Time
= ---
So to do a given amount of work, you can either operate at a high power for a short time or a low power for a
long time. For example: an explosion may convert a certain amount of chemical energy to heat in a fraction of a
second, which means it is relatively powerful; when you
run up and down stairs you are also converting chemical
energy (from the food you eat) into heat, but at a much
lower rate.
Power is most commonly measured in Watts (1 Joule per
Second (kW) which is simply 1000 Watts.)
1 Calorie
=
4,200 Joules
The Human body requires 2,000 calories or
SAOO,OOO Joules of energy per day.
The Watt
The Watt is the most common measurement
of power.
1 Watt = 1 Joule per second
A Watt hour is a measure of energy equivilentto
3600 Joules, because it is the amount of energy
consumed when one Watt is used over an hour
(1 Joule per second times 3,600 seconds). The
kiloWatt-hour (kWhL kilo meaning 1,000, is
1,000 Watt-hours or 3,600,000 Joules. This
is the energy you would need to run a 1,000
Watt stove for an hour. The kWh is the unit
Half a pound of dynamite contains approximately 150 used when you pay your electricity bill. A kWh
Calories of chemical energy, about the same amount of typically costs about 15 cents.
energy that is in a cupcake. When dynamite explodes the
bonds between the atoms rearrange and release energy Usinga 60 watt light bulb for one hour consumes
extremely quickly. This rapid release of energy gives the 0.06 kilowatt hours of electricity. Using a 60 watt
explosion a high power, even though the energy involved light bulb for one thousand hours consumes 60
is fairly small.
kilowatt hours of electricity.
A 155 pound man uses the same amount of energy to If a 60 watt light bulb is on all day for one
climb up stairs for an hour as used in an explosion of half week, the energy used is given by:
a pound of dynamite. Power is work done determined by
the rate in which it is done.
=
x x ~
Energy 0.06 24 7 10 kWh
At 15 cents per kWh that's only one dollar
When a person consumes a cupcake, the Calories and fiftey cents!
contained in it are broken down by the body, releasing
energy. That energy allows the human body to perform
the basic functions required for life, including movement.
Utilizing the energy, our bodies can perform the work
through muscle contraction. The recommended daily
Calorie consumption for a human is 2,000 Calories.
These Calories are matabolized by the body and provide
the person with the energy needed to do work throughout
the day.
w
Gaspard Gustave Coriolis
. (1792-1843)
Introduced the concept of work.
He defined work as the transfer of
energy acting through distance.
is for Work
Work is defined as the transfer of energy caused by a force acting though a distance. To solve for work,
you need to know the force being exerted upon an object as well as the displacement the object moves
whilst the force is acting. Once the force ceases to act, there is no further work done on the object, even
though the object may continue to move. To find how much work is being done, you multiply the force
and displacement together. The equation for work is therefore W = F . d
If the force is not great enough to move the object, then the amount of work done on the object is zero
as the displacement is zero.
•
Solving for Work
If the girl to the right pushes on a 0.7 kg ball with a
force of 55 Newtons, it will accelerate. If her hand
is in contact with the ball over a 0.3 meter distance,
we can find the amout of work the girl has done on
the ball using the equation for work:
Start off by using the work formula
W=F·d
W
=
55N
W
=
16.5J
X
O. 3m
Plug in the given values. F is the applied force,
and d is the displacement of the object
The total amount of work is 16.5 Joules
The ball then travels in a parabolic path, landing on the ground 3.5
meters away, and 1.8 meters below the girls hands. How much work
is done on the ball in flight? Keep in mind that the force is now different. Although the girl is doing no work, it doesn't mean that no work
is done. Gravity acts and gives a force given by F = m . 9 making
The man pulls on the pulley with a
the force 6.8 Newtons.
force greater than the weight of the
W=F·d
block (100 Newtons). The block will
Notice the distance is the vertical displacement
rise and the man will be doing work
W = 6.8K x 1.8m of the ball NOT the full trajectory
on the block.
Work in a Pulley
W
=
12.24J
The total amount of work is 12.24 Joules
When Work is Zero
If either force or distance is absent from the equation, work will
equal zero meaning no work will be done. The man to the left pushes
against a wall applying a strong force. The wall is not moving and so
the displacement is zero. The work he is doing on the wall is therefore
zero.
If a 2 ton truck were coasting down a level street maintaing a constant
speed, work done is again zero. Although there are very large forces
acting on the truck (gravity causes a huge downward force, and the
reaction from the road provides another force acting upwards) none
of these forces act in the direction of the dispacement, which is
hoizontal. Since the horizontal force component is zero, work is zero.
is for X-Rays
When X-Rays are passing through matter, some of
the energy packets known as "photons" interact with the
particles of the object and the energy is absorbed (a process
known as attenuation). Other photons pass through the matter without
interacting with any particles. How many photons that are able to
pass through the object is determined by the its energy and by
the atomic number, density and thickness of the object. The more
dense a material is, the more likely it is that the photons will be
absorbed by it. That is why it is easier for X-Rays to pass through
lighter atoms like the ones that make up your flesh and harder
for them to pass through heavier atoms like the ones that make
up your bones.
The most commonly used method of detecting X-Rays is with
photographic film. Because X-Rays are very similar to visible light rays,
they both
cause film to
be exposed. However, the film used
for X-Rays is often more responsive
to X-Rays' wavelength. Another
method, which is becoming much
more common is digitally, the same
Attenuation
process in which digital cameras
~ (Interactions)
work.
•
The image on the right shows
how the photons of an X-Ray are
absorbed when they pass through
an object. The amount absorbed
depends on the object's thickness,
density, and atomic number.
~
Thickness
~DenistY
Atomic Number(z)
It is possible for the energy of X-Rays to damage some of your body's cells. Although it is very rare,
some cells may receive genetic damage and even turn cancerous. Reproductive cells are at higher
risk than other cells. Even though you are much more likely to have cell damage from natural
radiation, you should try to keep your exposure to X-Rays to a minimum.
The photo to the left shows a hand that has
been damaged by high X-Ray exposure.
300 - 500 rem
Erythema (skin reddening)
300 - 500 rem
Temporary hair loss
700 rem
Permanent hair loss
1000 rem
Transepidermal injury (skin burns)
2000 - 3000 rem
Dermal radionecrosis (tissue death)
Type of Radiaton
Wavelength (m)
Radio
Microwave
Infrared
103
10-'
10-5
10'
108
10"
Visible Ultraviolet X-Ray Gamma-Ray
.5x10-8
10-8
10-10
10-"
Frequency (Hz)
1015
10 '6
1018
10'0
The image above shows X-Rays location on the electromagnetic spectrum. X-Rays are the type
of radiaton between Ultraviolet and Gamma-Ray. X-Rays have a wavelength from .01 to 10
nanometers. The frequency of an X-Ray ranges from 30 petahertz to 30 exahertz.
Properties of X-Rays:
1. Travel in straight lines at the speed of light.
2. Can't be detected by human senses.
3. Penetration depends on their energy and the matter they are traveling through.
4. Energetic enough to ionize matter and can damage or destroy living cells.
5. Their paths can't be changed by electrical or magnetic fields.
6. Can be slightly diffracted at junctions between two different materials.
is for Yucca Mountain
Yucca Mountain, a piece of federally owned land in Nevada, is the future location of the United States'
first permanent nuclear waste repository. Once the plans have been approved and construction completed,
70,000 tons of radioactive waste from temporary storage facilities across the United States will be stored in
Yucca Mountain .
........lIjii~ The
majority of the United States' nuclear waste is currently
stored in temporary facilities. Many spent nuclear fuel
assemblies are kept in large pools of water at the nuclear
power plant, where they must be carefully monitored to
prevent the waste from initiating any uncontrolled nuclear
reactions. Fuel assemblies are often left in those pools for an
indefinite amount of time. Nuclear waste is also stored above ground in
heavy steel containers called "dry casks," which are not meant to survive
more than a few decades.
The solution that Yucca Mountain is planning to implement is called
"deep geologic disposal." The waste will be put into canisters that are
specially designed to endure hazards such as earthquakes,
volcanic eruptions, extreme temperatures, and corrosion for the
next 10,000 years. After all of the waste has been put into
storage, it will be supervised for the first hundred years of the
site's operation, and then perma nently sea led off.
Nuclear waste will be stored in tunnels inside of Yucca Mountain.
It is impossible to attempt to foresee all of the forces that will be acting on Yucca Mountain thousands of
years in the future. This makes it difficult to design containers that will be able to hold the waste in Yucca
Mountain that will satisfy the security demands of the public. Some of the most prominent components of
high level waste are unstable by-products offission power, such as strontium-gO. They are highly radioactive
and long lived. Strontium-gO is a thousand times more radioactive than regular uranium, and takes about
10,000 years for it to decay to the same level of radioactivity as uranium that is already found in the earth.
However, the containers for the waste do not have to be completely and totally secure for that long. The
radioactivity of the waste will decrease exponentially over time. After 300 years, the strontium-gO will only
be a hundred times more radioactive than ordinary uranium ore, as opposed to a thousand.
Proposed Waste Package Design
Five cylinders filled with high
level waste are grouped
together with one used fuel
assembly.
They are placed into a SOmm inner canister made out of
nuclear grade stainless steel, which is encased by a 20mm
outer canister made out of a corrosion-resistant alloy. The
outer canister is very difficult to fracture and can last for
thousands of years.
These waste packages will be
shielded from water and falling
debris by a titanium drip
shield, which overhangs the
entire tunnel.
is for Absolute Zero
-459° F
-273° C
o Kelvin
Absolute Zero cannot be reached experimentally, although it can be closely
approached.
Absolute Zero represents the coldest temperature that
anything in our universe could ever reach. As far as we know, it
is possible to heat objects up indefinitely - there is nothing to
stop an object from getting hotter and hotter as we heat it more
and more. When we think about temperature, we think about
how hot or cold something is. What we are actually measuring
when we read the temperature of a substance is the average
kinetic energy that the molecules in that substance have. As we
cool an object, the kinetic energy of each molecule decreases,
and at absolute zero, there is no kinetic energy at all. Since
kinetic energy is a measure of speed, at absolute zero all
molecular motion stops. If we were to take an ideal gas and cool
it, as we approached absolute zero the gas would have no
pressure or volume. To get a feel of how cold absolute zero is
think about walking outside in -459° F weather!
=
OF
=(1.8 x 0c) + 32
F Degrees Fahrenheit
C = Degrees Celsius
Kelvin
=°C + 273.2
As objects get colder, it becomes increasingly difficult to cool
them further. There is always heat from something - the walls of
a container, the cooling machinery, and the measuring
equipment all allow a little bit of heat to sneak back into the
system. This is why we can never completely remove an object
from the rest of the universe. It is theoretically impossible to
reach absolute zero. Scientists have come very close, however,
and the coldest temperature that was ever reached here on
Earth was one half of a billionth of a degree above absolute zero.
The diagram on top shows liquid hydrogen
climbing up a surface as a superfluid. It is trying
to equalize itself with the hydrogen inside of the
"U" shaped object. The drawing below that
shows a basic interpretation of viscosity. The
green liquid represents high viscosity and the
blue liquid represents low viscosity. It is simply
showing the difference in thickness.
Atoms thot ore Heoted
88&&8Bff588
Atoms close to Absolute Zero
Above are two examples of temperature affecting the speed of atoms. The one
to the left shows warm atoms and the one to the right shows atoms at the
absolute zero state. Atoms at high temperatures move rapidly, while atoms at
absolute zero don't move at all.