Download Chemical Energy

ENERGY!!!
Part One:
Basics and Definitions
Energy is…
• Energy is the ability to do work.
• Work is movement. Energy is
expended to move objects from one
place to another.
• Forces acts on things (matter) to
create energy (movement).
How is energy measured?
• The scientific unit for energy
is the Joule (J)
• One joule is defined as the amount
of energy used when one Newton of
force moves an object 1 meter.
• Energy = Force applied (N) x
distance moved (m).
How is energy measured?
• If it takes 50 Newtons (N) to
move an object 20 meters (m),
then 1000 Joules (J) of energy
were used.
• 50N x 20m = 1000 J
How is energy measured?
• Energy can also be measured in
Calories.
• 1 food Calorie = 4184 Joules
Is one Joule a lot of energy?
• A typical candy bar has about
1 000 000 Joules of energy in it.
• A stick of dynamite has about
2 100 000 Joules of energy in it.
• That means that two 240 calorie
candy bars have as much energy
as a stick of dynamite!!!
Gummy Bear Sacrifice!!!
Part Two:
The Law of Conservation
of Energy
The law of conservation
of energy
• Energy cannot be created
or destroyed!!
• The amount of energy in the universe is
constant (we’re pretty sure…)
• Energy can change form from
one type of energy to another.
The six types of energy
•
•
•
•
•
•
Mechanical Energy
Chemical Energy
Thermal Energy
Electrical Energy
Electromagnetic Energy
Nuclear Energy
Example of energy changing
form:
• The chemical energy from
gasoline in a car transforms into
mechanical energy (the
movement of the pistons in the
engine) and thermal energy (the
heat caused by friction in the engine
block).
More examples of energy conversion
can be found at the end of this
presentation.
Part Three:
Mechanical Energy
Mechanical Energy
• Mechanical energy is associated with
the motion and position of objects.
• Mechanical energy is broken into two
categories:
• Kinetic Energy = Energy of moving
things
• Potential Energy = Movement stored as a
result of position.
Total Mechanical Energy is the
sum of Kinetic Energy and
Potential Energy
ME = PE + KE
Kinetic Energy
• Can be calculated if you know an
object’s mass in kilograms (kg)
and its velocity in meters per
second (m/s).
• KE = ½
2
mv
Kinetic Energy
• A one ton truck travels at 60 miles per hour.
How much kinetic energy does it have?
• First convert units to metric.
• A 1000 kg pickup truck travels at 27 m/s.
• KE = ½ x 1000 x 272
• KE = 364 500 Joules
Potential Energy
• Potential energy is stored
movement.
• Movement can be stored as a
result of shape or position.
Potential Energy
• Examples:
• A rock on a high cliff can fall.
• A stretched spring or rubber band
can snap back.
Gravitational Potential Energy
• PE stored in objects as a result of their height
off the ground can be measured if you know
the objects Mass in kilograms (kg), its
Height off the ground in meters (m), and
the Acceleration due to gravity (9.8m/s2)
• Gravitational PE = mgh
Gravitational Potential Energy
• A 1000 kg truck drives off a 50
meter cliff. How much potential
energy does it have the moment it
leaves the cliff?
• PE = 1000kg x 50m x 9.8m/s2
• PE = 490 000 Joules
Potential Energy turns into
Kinetic Energy.
• As the weight falls its
potential energy is
converted into kinetic
energy.
• Before it falls 100% of
the mechanical energy is
PE.
• The moment before
impact 100% of the
mechanical energy has
been converted to KE
Practice using the KE and PE
equations to solve the following
problem
Assume this is a frictionless
Environment.
Mechanical Waves.
• Mechanical Energy can move
from place to place as a
mechanical wave.
• Mechanical waves require
matter to move through. We
call the matter a Medium.
Mechanical Waves.
• The matter that carries a
mechanical wave is called a
medium.
• Examples of different mediums:
• Air
• Water
• Earth
Types of Mechanical Waves
• Longitudinal Wave: Particles in
medium move parallel to the
direction of wave motion.
Example: Sound waves, and
earthquake primary waves.
• Like a Slinky.
Types of Mechanical Waves
• Transverse Wave: particles in
wave move perpendicular to the
direction of movement. Example:
Earthquake secondary waves.
• Like a Jump rope.
The following link may help you to understand
the difference between wave types:
Types of Waves
Parts of a Wave:
Parts of a Wave:
• Wavelength – The shorter the
wavelength, the more energy the
wave delivers per second.
• Amplitude – The bigger the
amplitude the more energy the wave
has.
Part Four:
Thermal Energy
Thermal Energy
• Thermal Energy is the
vibration of particles in a
substance.
• Temperature is a measurement
of average kinetic energy of the
particles in a substance.
Particles of Hot air move faster
than particles of Cold air.
Temperature and State of Matter
• The hotter a substance is, the faster its
particles move.
• Eventually the particles in a solid substance
vibrate so much that the substance liquefies.
• If the liquid particles continue to heat up,
they will eventually have enough speed to fly
away and evaporate becoming gas.
• Gas particles are moving too
fast to stick together.
• Particles in a liquid are rolling over
each other and mixing. They still have
too much kinetic energy to form a
uniform structure.
• Particles in a solid still vibrate, but
their order remains consistent
Thermal Energy Transfer.
• Thermal energy flows from
warmer areas to colder ones.
Thermal Energy Transfer
• Convection – Mass movement of particles in a
fluid (like air, water, or magma) when the hot
areas of the fluid rise above the cooler ones.
• Conduction – Through objects in contact.
Vibration of the particles in one substance
transfers to the other substance. (Like when
energy is transferred between billiard balls)
• Radiation – Hot particles can lose kinetic energy
by turning it into Infrared Radiation. When this
happens the ‘heat’ is no longer thermal energy.
Conduction – Vibration of one
particle is passed to the next particle.
Convection – Hot fluid rises, cool
fluid falls.
Radiation – Vibrations of particles
give off Electromagnetic Energy in
the form of Infrared Radiation.
This heat is no
longer moving
particles. It has
turned into a type
of light.
Infrared Radiation can be seen
with special cameras.
Part Five:
Electrical Energy
Electrical Energy
• A form of energy resulting from the
flow of charged particles, such as
electrons or protons.
Electrical Energy
• Particles flow because of the attraction
between positive and negative charges.
• When positively and negatively charged
particles are separated, they are attracted
to each other.
• If they have a way to get to each other
they will flow.
These batteries have charges separated from one another. When
connected by a wire the charges flow until they can reach each
other and become neutral
Electricity Vocabulary
• Current
• Voltage
• Resistance
Current (I)
• Electric current is a flow of electric charge
through a conductor (usually a wire).
• This charge is typically carried by moving
electrons, but any flow of charged particles
(protons, ions, or electrons) is considered an
electrical current.
Voltage (V)
• Voltage is the potential to develop a current
through a conductor (like a wire).
• The higher the voltage, the bigger the
maximum current that can be pushed
through a wire.
• Example: A 9V battery can deliver bigger
current than a 1.5V battery.
Resistance (R)
• Electrical resistance is the opposition to the
passage of an electric current through an
object.
• Refers to how well something conducts.
• Metal conducts electricity well and has low
resistance. Rubber doesn’t conduct electricity
because it has a high resistance.
Ohm’s Law
• Ohm’s law describes the
mathematical relationship
between Voltage (V), Current (I),
and Resistance (R).
• V = IR
• This analogy helps explain the relationships in Ohm’s Law. V = IR
• The water tank represents Voltage, how much water is available to flow.
• The tap represents Resistance because it keeps the water from flowing
out all at once. Only so much water is allowed through.
• The stream of water represents the Current.
Circuits
• An electrical circuit is a closed loop giving a
return path for the current.
• In the case of a battery, electrons flow from
the negative node to the positive one.
• There are three types of basic circuit.
• Simple
• Series
• Parallel
Simple Circuit
• A simple circuit allows
electrons to flow from
one side of the battery
to the other.
• The electrons flow
through the bulb and
some of the electrical
energy is converted to
light (electromagnetic
energy) and heat
(thermal energy).
Series Circuit
• Circuits in series lose voltage
through each component.
• These bulbs will both be dim
because the same current must
light both bulbs.
Parallel Circuits
• Circuits in parallel
don’t lose voltage
through each
component.
• These bulbs will both
be bright because they
have their own separate
current.
Electricity Generation
• Where does our electricity come
from?
• Our household electricity is
produced by changing other types
of energy into electrical energy.
• This is called an energy conversion.
Example of converting energy into
electricity:
• Coal (Chemical Energy) gets
burned  Heat (Thermal Energy)
boils water  Steam turns a turbine
(Mechanical Energy)  Turbine
runs a generator. Generators turn
mechanical energy into electricity
(Electrical Energy).
Want some extra credit?
Build a simple generator!
Ask me how ;-)
Problems with Power Production
• All methods of power generation
have disadvantages.
• Generally producing electricity is
either expensive, dirty, dangerous,
non-renewable, or it destroys the
environment.
Part Six:
Nuclear Energy
Einstein and Nuclear Energy
• Albert Einstein figured out that all matter
contains unexpectedly HUGE!?! amounts
of energy!!
• E = mc2
• Energy (E) equals mass (m) multiplied by the speed
of light (c) squared.
Einstein and Nuclear Energy
• His discovery was so shocking because no
one had ever seen matter yield this much
energy.
• Our biggest bombs at the time could only
release tiny amounts of energy compared to
what Einstein predicted could be released.
Einstein and Nuclear Energy
• If we burned 3 kilograms of gasoline (about 1.05
US Gallons or 3.97 liters), it would yield
140,000,000 Joules.
• This is a lot of energy but burning something only
releases the CHEMICAL ENERGY.
• There is still a HUGE amount of energy trapped in
the nuclei of the gasoline atoms.
• Energy trapped inside the nucleus of an atom is
called NUCLEAR ENERGY
Einstein and Nuclear Energy
• If we took that same 3 kilograms of gasoline
and broke open every single atom in it we
would release 2.7 x 1017 Joules of energy!
• This is almost 2 billion times the energy we
obtained from the "ordinary" burning of one
gallon of gasoline!
The Basic Atom
Lots of energy inside!!
Basic Atom Vocabulary
• Nucleus - The very dense region, consisting
protons and neutrons, at the center of an atom.
• Proton - A subatomic particle in the nucleus with
a positive (+1) electric charge.
• Neutron – A subatomic particle in the nucleus
with no charge (+0). (It is neutral)
• Electron – A subatomic particle outside of the
nucleus with a negative (-1) charge.
Basic Atom Vocabulary
• Atomic Number – The number of
protons in the nucleus of an atom.
• Atomic Mass – The number of protons
+ neutrons in the nucleus of an atom.
Nuclear Energy
• Nuclear energy is stored inside
the nuclei of atoms.
The Basic Atom
Lots of energy inside!!
Nuclear Energy
• Nuclear energy can be released in two
ways:
• Nuclear Fission
• Nuclear Fusion
Nuclear Fission
• Nuclear fission means: To split the
nucleus.
• Nuclei are very difficult to split.
• Splitting a nucleus can be accomplished by
shooting it with radiation (like in a nuclear
bomb), or crashing it into another nucleus at
very high speed (like in a particle accelerator).
Fission in a
nuclear reactor:
Nuclear Fusion
• Nuclear fusion means: To
combine two nuclei into one.
• Positively charged Nuclei repel each other.
• Forcing two nuclei to combine takes A LOT
of force. (like the pressure inside a star)
Nuclear Fusion in a Star:
• A Star is a massive ball of Hydrogen being
crushed by gravity.
• Eventually the pressure in the center of a star
is so great that Hydrogen (H) atoms begin to
fuse together to form Helium (He).
• Nuclear fusion in a star is what creates
the all of the energy that a star releases.
Balanced forces in a Star:
Part Seven:
Electromagnetic Energy
Electromagnetic
(EM) Energy
• Waves of electrical and magnetic
energy moving together through
space at light speed.
• Also called electromagnetic
radiation.
Types of Electromagnetic
Waves
•
•
•
•
•
•
•
Radio Waves
Microwaves
Infrared Light
Visible Light
Ultraviolet Light
X-rays
Gamma Rays
Electromagnetic Waves
vs. Mechanical Waves
Mechanical Wave
Electromagnetic
Requires medium to travel
Can travel in a vacuum
Can have many frequencies,
amplitudes, and speeds.
Can have many frequencies &
amplitudes.
Only one speed: 3.00 x 108 m/s
Created from vibrations of
electrons
Just keeps going forever
Created from vibrations of
large masses
Lose energy as they travel
Parts of an
Electromagnetic Wave:
Parts of an
Electromagnetic Wave:
• Wavelength and Frequency – The
higher the frequency the more energy the
wave delivers per second.
• Amplitude – The bigger the
amplitude the more energy the wave
has.
A prism can be used to bend different wavelengths of colored light
found in ‘white light,’ which isn’t really white. Really it’s all the colors
mixed together.
Electromagnetic Waves.
• We can see visible light with our eyes,
but most of the wavelengths in the
electromagnetic spectrum are invisible
to us.
• There is a whole world of light
surrounding us that we cannot detect
with the naked eye.
•
Just ask Sir Frederick William Herschel how he discovered Infrared ;-)
Bug’s-Eye View of a Narcissus
Visible Light
Ultraviolet Light
Scientists use special cameras to
see different wavelengths of EM
radiation.
• This is what the
sun would look
like if you
could see (top left to
bottom right) X-rays,
Ultraviolet
Light, Infrared
Light, and
Radio Waves.
Looking at different types of EM radiation
tells us a lot about what’s happening in
deep space.
• Take the following example of
‘The Crab Nebula’
• The Crab Nebula is the remnant of a
supernova explosion that was seen on
Earth in 1054 AD. It is 6000 light years
from Earth.
Crab Nebula in Visible Light
This picture of The Crab
Nebula in Ultraviolet light
shows us where majority of
the energy is.
When seen in X-ray the structure of the Crab Nebula Comes into focus.
At the center of the bright nebula is a rapidly spinning neutron star, or
pulsar that emits pulses of radiation 30 times a second!!
Part Eight:
Chemical Energy
Chemical Energy
• Chemical Energy is stored in the
chemical bonds between atoms.
CH4
H2O
NH3
Chemical energy in chemical
bonds
• Multiple atoms can bond together into
larger molecules.
• It takes energy to form these chemical
bonds.
• Breaking chemical bonds releases the
trapped energy.
Chemical Energy
vs. Nuclear Energy
Nuclear Energy
Chemical Energy
Stored inside the
nucleus of an atom.
Stored in bonds
between atoms.
Holds the nucleus of an Holds multiple atoms
atom together.
together.
Chemical energy and
combustion.
• A good way to release the chemical
energy in something is to burn it.
• When a substance is burned chemical
bonds in the molecule are broken and
the energy comes out in the form of
heat and light.
One molecule of propane can be burned with five
molecules of oxygen creating three molecules of carbon
dioxide and four water molecules.
Chemical energy is trapped in the bonds holding
propane together. When it burns all of these bonds are
broken, releasing energy.
Chemical Energy and You
• You get your energy from burning a
high-energy molecule called
‘Glucose.’
• Glucose is a large molecule with
many chemical bonds.
• Glucose: C6H12O6
Look at all those
Chemical bonds!!
Glucose!
The law of conservation
of energy
• Energy cannot be created
or destroyed!!
• The amount of energy in the universe is
constant (we’re pretty sure…)
• Energy can change form from
one type of energy to another.
Energy
Conversions!
Can you identify the energy
conversion pictured?
In this example chemical energy in fireworks
is transformed into light (electromagnetic
energy).
• Chemical (Rocket Fuel) 
Thermal Energy (Heat) +
Electromagnetic Energy (Light)
+ Mechanical Energy (Flying
Rocket).
• Mechanical energy
• Potential Energy (PE) 
Kinetic Energy (KE) + Sound
(mechanical wave).
• Electrical  Mechanical Energy
(sound waves are mechanical
waves)
• Chemical Energy (in the riders
food)  Mechanical + Thermal
Energy
• Nuclear  Heat + Light +
Sound Energy.
• Mechanical Energy (PE stored in
water at the top of a hill) 
Mechanical Energy (KE of
falling water transfers to the
spinning turbine)  Electrical
Energy.
• Electromagnetic Energy 
Chemical Energy.
• Plants use light to build chemical
bonds in glucose.
• Chemical (gasoline) 
Mechanical Energy.
Can you think of any other
types of energy that can be
converted?