Download 101 Science Misconceptions

101 Science Misconceptions
by Michael Doig & John Herrera
illustrations by Ramsey Ess
101 Science Misconception
1
Table of Contents
Astronomy .................... 3
Biology .................... 6
Chemistry .................... 7
Earth’s Motions .................... 10
Electricity .................... 12
Geography .................... 14
Geology .................... 15
Measurement .................... 16
Meteorology .................... 19
Myths .................... 21
Physics .................... 23
Temperature .................... 27
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Copyright © 2008 Michael Doig. Some rights reserved.
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Astronomy
#1 – The Earth is larger than the Sun.
Looking at the image above, the Sun is extremely large and the Earth is a tiny
dot. The diameter of the Sun is roughly 862,400 miles. The Earthʼs diameter is
7,900 miles. That means that the Sun is more than 100 times larger in diameter
than our planet. In terms of mass, the Sun is over three hundred thousand times
heavier than the Earth!
#2 - The Sun will never burn out.
Just like people, stars have a life span. In roughly 5 billion years, the Sun will
begin to run out of hydrogen in its core. The helium in the core will contract and
cause the Sun to bloat and eventually burn out. Our solar system, including the
Earth, will be destroyed when this happens.
#3 - The Sun is not a star.
Our Sun is a normal main-sequence G2 star,
one of more than 100 billion stars in our
galaxy. It is often said that the Sun is an
"ordinary" star. That is true in the sense that
there are many others similar to it. But there
are many more smaller stars than larger ones;
the Sun is in the top 10% by mass. The
median size of stars in our galaxy is probably
less than half the mass of the Sun.
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#4 - Meteors are falling stars.
A meteor is the visible event that accompanies the entry of a meteoroid into the
atmosphere. A meteor is basically light. A meteoroid is not a star either, it is
debris that comes from outer space and enters our atmosphere from time to time.
Meteoroids can range in size from a particle of sand to a boulder. Obviously, the
larger ones draw more attention.
#5 - The solar system is extremely crowded.
Distances in the Solar System are measured
in astronomical units (or AU). One AU is about
the distance between the Earth and the Sun.
Pluto is about thirty eight AU, meaning it is
thirty eight times farther from the Sun than
Earth is. The solar system contains the Sun,
eight planets, their 166 moons, three dwarf
planets and billions of small bodies that
include asteroids, comets and interplanetary
dust that all have plenty of room to move
around.
#6 - In a constellation, all of the stars are near each
other.
Each constellation is a collection of stars that are distributed in space in three
dimensions – the stars are all different distances from Earth. The stars in a
constellation appear to be near each other because we are viewing them from
very, very, far away.
#7 - The brightness of a star is only dependent on its
distance from Earth.
Stars vary greatly in size, distance from Earth, and temperature. Dimmer stars
may be smaller, farther away, or cooler than brighter stars. By the same token,
the brightest stars are not necessarily the closest. Of the stars in Cygnus, the
swan, the faintest star is the closest and the brightest star is the farthest!
#8 - The Universe is static.
There is a saying that states “nothing is static”. The Hubble Space Telescope has
given readings that show the Universeʼs precise expansion rate and given
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scientists the data to conclude that the Universe is expanding faster and faster as
time progresses and will never stop.
#9 - The Universe contains only the planets in our solar
system.
Our solar system is part of the Universe but so is everything else that exists, has
existed or will exist. Yes, that is a pretty broad definition, but the Universe does
not depend on specifics. Space and time, matter and energy, and physical laws
governing them all fall under the heading of the Universe.
#10 - The Sun goes around the Earth.
From Earth it would make sense that the Sun orbits the Earth. However, the Sun
happens to have the honor of being the solar systemʼs center – meaning that
everything else revolves around it. Smaller objects orbit around larger objects
and as you read earlier the Sun is much larger than the Earth.
#11 - The North Star is the brightest star in the sky.
Star brightness is measured using the scale of
apparent magnitudes. The brighter the object
appears, the lower the value of its magnitude. The
apparent magnitude of the North Star, Polaris, is
1.97 – making it barely in the top fifty brightest
stars. The brightest star in the sky (besides the
Sun) is Sirius, which has an apparent magnitude of
-1.47 (yes, minus).
#12 - The surface of the Sun is
without visible features.
Sunspots are the most immediately visible features on the surface of the Sun.
They are the cooler, darker areas and are associated with intense magnetic
activity. They can be visible from Earth without the aid of a telescope.
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Biology
#13 - Evolution can happen to a single organism.
If you are born a human, you are going to die a human. Evolution happens in the
genes of a population over the span of generations. You will not see any
evolutionary changes among humans during your lifetime. You could, however,
witness evolutionary change in organisms that have short life-spans such as
bacteria or insects.
#14 - Koalas are bears and Jellyfish are fish.
Koalas are marsupials, belonging to
the same group as kangaroos.
Jellyfish are Cnidarians, as are corals
and sea anemones. Scientists
usually call them “sea jellies” since
they are not, in fact, fish. This is one
of the problems with common names.
#15 - Some human races
are older than others.
The most scientifically supported
theory as to the origin of humans is
the “Out of Africa Hypothesis”. DNA
evidence has suggested a common
ancestor for all modern humans, one
who existed around 200,000 years
ago in Africa. The oldest fossil
evidence of modern humans was
found in this region and dates back 130,000 years. The differences in skin color
(and other anatomical differences) came about as humans spread out across the
world and adapted to their environments.
#16 - Acquired characteristics can be inherited.
The dictionary definition of the term acquired is “to gain for oneself through oneʼs
actions or efforts”. Therefore, an acquired characteristic is one that you pick up in
life due to the circumstances and events that you participate in. Another person
can not inherit the same characteristics because they have not been through the
exact same circumstances and events that you have. Just because your father
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was a great drummer doesnʼt guarantee you will be too.
#17 - Polar bears eat penguins.
Polar bears live in the Arctic and penguins live in the southern hemisphere near
Antarctica. It would be difficult for the bears to eat creatures who live so far away.
The diet of a polar bear actually consists of seals, young walruses and whales.
#18 - We see because light illuminates the world.
If the only requirement for sight was the presence of light, there would be no
blind people on Earth. Light does play a part in sight but it is the mechanisms
inside the eye that make it happen. The lens of the eye focuses the image of
what it “sees” onto the retina, a light sensitive membrane at the back of the eye
that is actually a part of the brain. The retina converts the light patterns into
neuron signals. The brain puts together the signals to determine what is being
seen.
Chemistry
#19 - The Earth has 92 chemical elements.
A chemical element is a type of atom, like hydrogen or oxygen. As of January
2007, 117 elements have been observed by scientists, with 94 of these elements
occurring naturally on Earth. 23 elements are artificially created, in nuclear
reactors or particle accelerator experiments.
#20 - Radioactivity is man-made.
There are actually three naturally occurring
radioactive series in the periodic table: the uranium,
actinium and thorium seriesʼ. The nuclear reactions
of these occur spontaneously and decay through
alpha and beta emission until they end at a different
stable isotope of lead.
#21 - Oil and water don’t mix
because the molecules repel each
other.
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To the contrary, oil molecules are attracted to water molecules more so than
other oil molecules. When a droplet of oil hits the surface of the water it spreads
out, proving the attraction. The reason the substances stay separated is that the
water to water molecular attraction is stronger than the oil to water molecular
attraction.
#22 - Salt water is full of sodium chloride molecules.
Table salt is made of sodium chloride molecules. When salt dissolves, however,
the material turns into the independent entities of sodium and chlorine. Salt water
is rich in sodium and chlorine but contains no sodium chloride. The water
separates the atoms well enough that they can not bond in the body of water.
#23 - Solid particles have no motion.
Particles of solids do have motion, but not as much as you would find in other
states of matter. Solids have a high density, meaning that the particles are all
tightly packed together. While they can sort of jiggle in place, they do not have
room to move past each other. It is the only state of matter in which the particles
are rigid in this way.
#24 - Positively charged objects have gained protons
rather than being deficient in electrons.
A positively charged ion is called a cation and there are fewer electrons than
protons. A cation does not become neutral (with an even number of protons and
neutrons) by gaining another proton. It would have to gain electrons. It would
also have to gain electrons to move from neutrality to being an anion or
negatively charged ion. See a pattern? The electrons are the ones that do all the
moving. A cation is deficient in electrons. The protons have not gone anywhere.
#25 - A chemical bond is a physical entity.
Chemical bonds are shared electrons and attraction forces. They are not a form
of matter on their own. Terms like shell, cloud and bond are used because it is
easier for us to understand physical terms than abstract ones.
#26 - Physical changes are reversible while chemical
changes are not.
Equilibrium reactions occurring in the forward and backward directions
simultaneously prove that a chemical change can be reversible. Even if a
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physical change is reversible, it does not mean it will be easy. Doubters should
try shattering and grinding down glass then restoring it to its original condition.
#27 - Electrons orbit atoms the way a moon orbits a
planet.
When drawing an atom and its
accompanying electrons, students and
teachers often find it easiest to represent
the electrons as traveling in circles around
the atom. The truth of the matter is that
electrons do not follow a simple circular
pattern.
#28 - The electron shell is like
an eggshell that is there to
protect the nucleus.
Electron shells are discussed at length in chemistry courses. The “shell” is not a
literal, hard physical layer. They are regions surrounding the nucleus where
electrons can be found. There are not any physical barriers separating (or
distinguishing) them.
#29 - The electron cloud is like a rain cloud with the
electrons suspended inside like water droplets.
Like the shell, the electron cloud is a misnomer. There is no cloud of matter of
any kind. It is merely a region in which electrons are constantly moving. Since
they are in constant motion, they obviously could not be suspended in the cloud.
This does not exist anyway.
#30 - Atoms can be seen with a microscope.
How many atoms would you guess can fit on a hair? If you said a number in the
hundreds or thousands, think higher. The width of a human hair has
approximately one million atoms. They are much too small to be seen by a
microscope.
#31 - Melting/freezing and boiling/condensation are
often understood only in terms of water.
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When a material moves between the three states of matter (solid, liquid and gas),
they pass through what is called phase transitions. These are the points at which
the material changes from one to the other. The melting/freezing point is the line
between solid and liquid. It is written that way because it is the same point.
Whether it is melting or freezing just depends on which direction you are
heading. The boiling/condensation point is the point in between gas and liquid.
These points are relevant to any material that can change phases, not just water.
#32 - Materials can only exhibit properties of one state
of matter.
Materials can exist in any of the states of matter. Water (a liquid) becomes ice (a
solid) when frozen and steam (a gas) when boiled. The properties of the original
material (water) change depending on what state it is currently in. For example,
the particles of water have the most freedom of movement as steam, a slightly
more restricted area of movement in a liquid and can merely jiggle as ice.
#33 - A gas will always expand to fill its container.
It is true that a gas will expand to fill the container it is placed in but that can only
happen if the container is completely empty. All of our standard containers are
already filled with air. If there is a vacuum, this could hold true, but those
instances are mostly just in the minds of physicists.
Earth’s Motions
#34 - Seasons are caused by the Earth’s distance from
the Sun.
It may seem probable that the
Earthʼs distance from the Sun is
what causes the seasons. But
consider the fact that the seasons
reverse once you cross the
equator. Argentina and Canada
are the same distance from the
Sun but have differing seasons.
As the Earth orbits the Sun, it is
also rotating on its axis. The Earth
is tilted on its axis, this tilt is what
causes the seasons. During the
summer months the north pole is
facing the Sun, and during the winter months the north pole is facing away from
the Sun.
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#35 - Phases of the Moon are caused by a shadow from
the Earth.
In order to understand why we see different “phases” of the Moon, it is important
to realize that the Moon itself does not produce any light. It merely reflects the
light of the Sun. The Moonʼs orbit around the Earth causes the Moon to change
its position in relation to the Sun. Only half of the Moon is ever lit up. When the
Moon is farthest from the Sun we see a full Moon. When the Moon is closest we
see a new Moon.
#36 - The Earth is the center of the
solar system. The planets, Sun and
Moon revolve around the Earth.
There was a time when the belief that the Earth is
the center of the solar system was the most
popular opinion. Of course, that time was in the 16th
century, before a man named Galileo disproved this
geocentric model. The real solar system
centerpiece is the Sun, around which we revolve.
#37 - The Earth is sitting on
something.
School book diagrams often show a rod looking
device sticking out of each end of the Earth to
demonstrate its axis. That is a learning device not a
replica of an actual object. The Earth (or any other
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planet) is not sitting on anything. When someone states this misconception, ask
them what they think the Earth could possibly be sitting on? It may provide some
amusing answers.
#38 - The Moon goes around the Earth in a single day.
Because it rises every night, it might seem like the moon would have to pass
around the world to come back to its place in the sky the next night. But it is the
Earthʼs rotation that makes the Moon seems to “disappear” and “reappear”. It
takes the moon a little over twenty seven days (27.3 approximately) to orbit
around the Earth. This is called a sidereal month. Since the Earth is orbiting the
Sun in the same direction as the moon it takes a little longer for the moon to
return to the same phase- about 29 and a half days. This is called a synodic
month.
Electricity
#39 - Ben Franklin’s kite was struck by lightning.
Amazingly, textbooks and encyclopedias are still
reprinting this as fact when it should be obvious that
anyone who is holding a kite that is struck by
lightning would be, at best, severely injured.
Franklin did head out into a thunderstorm with a kite
but there was no lightning bolt. The electric charges
present in the storm traveled through the kite string,
standing the hairs of the twine on end. The twine
charged a metal key which could then produce
sparks. The experiment showed him that some
storm clouds carry a strong electrical charge. He
then hypothesized that lightning was just a big
electric spark.
#40 - Electricity is a form of energy.
By now you have probably figured out there is a lot
of poor terminology used in science. Electricity does
not actually exist. It is an umbrella term that carries
different, contradictory meanings. If this is confusing, consider sound waves
which move through collections of air molecules. Electricity is like the air which is
vibrating, while the electrical energy is like sound waves which fly through the air.
Sound and air are two different things, just as energy and electricity are two
different things.
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#41 - Electricity is made of electrons.
Well, in the case of metal conductors this is true. The electric current that passes
through them is a flow of electrons. But electric currents in plasma and
electrolytes travel through electrified atoms. In the case of the electrolytes, the
electrons are not moving at all.
#42 - “Static electricity” is electricity that is static.
This is another one of those
scientific misnomers. Typically,
when we say something is static
we mean that it is unchanging.
“Static” electricity is a collection of
electrical phenomena where the
amounts of positive and negative
charge are not perfectly equal, the
voltage is high and current is low,
where electrical forces reach
across space and electric fields
are very important. Its that ability
to reach across space that causes
the cool “tricks” we have all
performed with static (like standing
your hair on end with a balloon).
#43 - Friction causes
“static electricity”.
This seems logical because we have all rubbed a balloon against our hair to
make it stand up. It isnʼt the friction, though, that causes this. “Static” electricity
happens whenever two dissimilar insulating materials touch and separate again.
When they touch, the surfaces become oppositely charged and imbalanced.
When they separate, this imbalance travels with them.
#44 - The direction of a current is from the negative to
the positive.
An electrical current does not necessarily flow from negative to positive. Granted,
the current is often being passed along by a stream of slowly moving electrons.
But in some situations the electric currents can be passing through a flow of
positive particles. Sometimes both positive and negative particles are flowing at
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the same time in opposing directions. It really just depends on the type of
conductor.
#45 - Electric energy is carried by individual electrons.
The energy in an electrical circuit flows
rapidly through a column of electrons that are
moving very slowly or (in the case of AC
circuits) vibrating slightly. Individual electrons
do not hold and carry a portion of the energy
to the end. Think of electrons as absorbers
rather than deliverers.
#46 - Electrical energy flows
inside of wires.
If you have electricity, there are wires that
connect to your home that are operated by
the electric company. Normally the electrical
energy does not flow inside of metals. In fact,
the electrical energy being sent out by
batteries and generators is located in empty
space: it takes the form of electromagnetic
fields surrounding the wires.
#47 - All metals are attracted to a magnet.
Pure gold, silver and platinum are not magnetic. If you hold your supposedly
precious metal ring to a magnet and it sticks, donʼt think that you have been
ripped off. Precious metals are soft and are combined with other metals (like iron
which is magnetic) before being crafted into jewelry. Some types of stainless
steel are also not attracted to magnets.
Geography
#48 - The Sahara is the world’s largest desert.
Technically, a desert is any region of arid land. It doesnʼt necessarily have to be
hot. The entire continent of Antarctica qualifies as a desert since it has almost no
rain, very little vegetation or animal life. That makes Antarctica the largest desert
with the Sahara holding the title for the largest hot desert.
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#49 - All rivers flow South.
All rivers do run downhill, and
most from north to south.
However there are many
rivers which flow north. The
Nile, which runs through
Africa, is the most famous
south to north running river.
Others that follow this
reverse path include the
Bann in Northern Ireland, the
Bighorn that goes through
Wyoming and Montana and
the Cauca in Columbia.
Geology
#50 - Continents are too big to move.
If continents did not move, there would be no Earthquakes and we would still be
living on Pangaea. Fossil records show identical specimens on continents that
are now far away from each other (like Africa and South America). This suggests
the continents were once connected. The continents are situated on plates that
shift due to the spreading of the sea floor. Movement of these plates is a major
cause of volcanic and seismic activity.
#51 - Any mineral which scratches glass is a diamond.
A diamond can scratch glass
because it is harder. The Mohsʼ
scale, which is used to determine
the relative hardness of minerals,
is measured from 1 to 10.
Diamonds are the hardest and
receive a 10 on the scale. Glass
has a hardness of about 6. Quartz
(7) and Topaz (8) are also harder
than glass and can therefore
scratch glass.
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#52 - The Earth is only 20,000 years old.
The age of the Earth has been estimated by geologists to be around 4.54 billion
years old. This finding is considered controversial by followers of some religions,
such as Christianity, which has established a much shorter timeline for the world.
Scientists have used the oldest known terrestrial rocks and analyzed the age of
other objects in the solar system to come up with the much older age.
#53 - Rocks are the same as minerals.
If you think of a rock as a brick wall, minerals are the bricks and the rock is the
entire wall. A rock is an aggregate of one or more mineral particles formed
through either crystallization of molten magma (igneous rocks), settling of
particles (sedimentary rocks), or reheating and pressure applied to pre-existing
rocks (metamorphic rocks), with no set chemical composition or atomic structure.
#54 - Rocks must be heavy.
Many rocks are heavy and dense. However, some rocks such as pumice are very
light and not very dense. In fact, pumice will float if placed in water because it is
less dense. Some people refer to pumice as a foot stone. It is an igneous rock
formed during explosive volcanic eruptions and is essentially puffed rock. Much
like Corn Pops are puffed corn!
#55 - Earth is molten, except for its crust.
Most of the surface of Earth is solid, and as you travel deeper into Earth much of
that solid rock becomes liquid due to heat and pressure. However, if you could
travel far enough into Earth you would run into the solid metal of the outer core.
Scientists know this because they have studied seismic waves from earthquakes
and they behave differently when they reach the outer core, suggesting it is solid.
Measurement
#56 - Mass, weight and density are equal values.
These terms of measurement are similar but are not equal. Mass is the quantity
of matter (which itself is a collection of atoms and molecules). Weight is the force
that the Earth pulls on the mass. Density is a measure of mass per volume – or
how much mass is in a given space.
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#57 - Heat is the same as hot.
We often use the words hot and heat interchangeably when they are, in fact,
different things. Hot is a temperature observation. Heat is the energy put into a
system that excites atoms and molecules into action. The more heat that is put
into a system, the faster those atoms and molecules move. This excitement can
cause the system to gain warmth but that isnʼt always the case.
#58 - Pressure and force are synonymous.
Pressure and force are related to one another but not synonymous. Pressure is
the force per unit area. Force is the pressure exerted on an area. In other words,
if you were setting up an equation with a certain area, you would need to know
the pressure to determine the force (or vice versa).
#59 - Gases have no mass.
Mass is defined as the quantity of matter. Matter is made up of atoms and
molecules. Breaking it down in this way should make it clear that gas would have
to have a mass since it contains atoms and molecules. Even more simply stated:
Gas is a state of matter and matter is a component of mass.
#60 - One degree of temperature is smaller on the
Celsius scale than on the Fahrenheit scale.
One degree Celsius is equal to about 34 degrees Fahrenheit so a Celsius degree
is larger. Letʼs compare a defined temperature measurement in both scales. The
boiling point of water is 100 degrees Celsius. In Fahrenheit, the boiling point is
212 degrees. They are two different ways of expressing the same temperature.
#61 - Wood floats and metal sinks.
If you think that all metal sinks;
drop a needle sideways onto the
surface of water. It will float.
Water has a unique property
called surface tension (caused
by strong molecular bonds) that
allows light objects like needles
and water strider insects to rest
on its surface. Some wood can
indeed float but only the wood
whose density is less than water.
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#62 - Objects float in water because they are lighter than
water.
We use the term “lighter” in terms of weight- if something weighs less than
another object it is considered lighter. Weight is the force the Earth pulls on the
mass of an object or substance. It is not what determines which material will
“float” above the other. Density – the amount of matter in a certain space
determines whether an object will float. In a substance with low density, the
atoms and molecules are moving quickly and spread out. A substance with high
density has slower moving atoms and molecules that are bunched together
tightly. Objects that float in water have a lower density than water.
#63 - Liquids of high viscosity are also liquids with high
density.
Viscosity is the level of resistance a liquid has towards flow. Honey has a higher
viscosity than water because it is harder for honey to flow. Viscosity can be
simply tested by pushing a spoon through the liquids and seeing which one flows
the easiest. Density has nothing to do with viscosity. It is the amount of mass of a
substance per unit volume. A dense material has a high mass per volume. It
doesnʼt matter how viscous it is.
#64 - Temperature is a property of a particular material
or object.
For example, metal is naturally cooler than plastic. The temperature of any
material can be increased or decreased quite a bit. If this wasnʼt true, phase
changes would not occurs. Heat can be applied or subtracted from any material
to cause a raised or lowered temperature. While substance A might have a
higher starting temperature than substance B, this temperature is dependent on
environmental situations that can change and shift the heat to substance B.
#65 - Hot and cold are not opposite ends of a
continuum. They are different things.
Temperature is a man made scale designed to help us determine when a
substance is going to boil or freeze, among other things. Warmth and coolness
(or hot and cold) are opposing aspects of this temperature continuum. There is
no real definition of what is hot and what is cold because they are relative, not
exact, terms.
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#66 - There is something wrong if the temperature
remains constant at boiling.
No, there is nothing wrong if the temperature of a substance remains constant at
boiling. This is actually how you find the standard boiling point of a liquid in a
laboratory. The liquid may begin to show a sign of boiling before the temperature
has stabilized but it is not considered to be at the junction between the phases of
liquid and gas until that temperature levels off.
Meteorology
#67 - Clouds and fog are made up of water vapor.
Clouds and fog are actually made of water in its liquid state. Small droplets hang
in the air after water vapor has condensed. Water vapor itself is transparent; fog
and clouds are visible.
#68 - There is such a thing as heat lightning.
There is only one type of lightning. Heat lightning is regular lightning visible to
onlookers too far away from the actual storm to hear the thunder or see the
clouds associated with it. Since the skies are often clear and warm evenings
favor this occurrence, the term heat lightning was born.
#69 - Storm clouds are charged by friction.
Scientists have not determined the
true explanation for the electrification
present in storms but they know
friction is not the answer. The clouds
do not “rub” against each other nor
does the rain cause friction with the
air as it falls from the sky.
#70 - Jet contrails are
smoke.
Contrails are condensation trails
made by the exhaust of aircraft
engines which precipitate a stream of
tiny ice crystals in the moist, frigid upper air. The main products of combustion
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are carbon dioxide and water vapor. At high altitudes this water vapor emerges
into a cold environment, and the local increase in water vapor can push the water
content of the air past saturation point. The vapor then condenses into tiny water
droplets and/or deposits into ice. These millions of tiny water droplets and/or ice
crystals form the contrails.
#71 - The moisture on the outside of a cool drink comes
from inside the drink.
The air around us is full of moisture, we call this humidity. The dew point is the
temperature that this water vapor will condense into water. The cold drink is at or
below the dew point for the surrounding air. Therefore, the water vapor
surrounding the bottle condenses and causes water to form on the outside of the
drink.
#72 - Air and oxygen are the same gas.
Air contains oxygen but they are not the same thing. Air is composed of a mixture
of 21% oxygen, 78% nitrogen and other trace gases. Oxygen gas is an essential
part of air since without it the human bodyʼs metabolic processes cannot operate.
If the air around us was pure oxygen it would be explosively flammable and fires
would not be a good idea.
#73 - Helium and hot air are the same gas.
“Hot air” is a warmed mixture
of oxygen, nitrogen and trace
gases. It causes a balloon to
float because the hot air is
less dense than the cooler air
around it.
Helium is also able to cause
things to float because of a
low density but heat does not
have to be involved in this
case. Helium is naturally one
of the lightest elements on
Earth because it has an
atomic number of 2 (only
hydrogen is lighter) and
therefore has a low density.
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#74 - The hole in the ozone layer is causing global
warming.
The ozone layer is a layer in our atmosphere that protects us from the Sunʼs
ultraviolet radiation. It has been depleted because of our use of CFCʼs. If the
ozone layer was destroyed we would have more instances of skin cancer,
sunburn and genetic mutation. Global warming on the other hand is caused by
the accumulation of carbon dioxide (from burning fossil fuels) in the atmosphere.
Carbon dioxide causes our atmosphere to retain too much heat and thus causes
global warming.
Myths
#75 - Humans are responsible for the extinction of the
dinosaurs.
If you have been sitting around blaming your ancestors for wiping out the
dinosaurs, you can breathe a sigh of relief. Humans did not evolve until about 65
million years after the dinosaursʼ extinction.
#76 - Scientists must adhere to a rigid set of guidelines
called “the Scientific Method”.
The Scientific Method is a technique taught in secondary schools that instructs
students to use a hypothesis, experiment and conclusion method. While this is
adequate in classroom laboratories and science fairs, it is not a widely held
doctrine of the scientific community. There is no big book of rules called the
Scientific Method that practicing scientists need to consult before an experiment.
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#77 - You can balance an egg on end during the spring
equinox.
Every year, without fail, some TV station broadcasts a news segment showing
local schoolchildren standing eggs on end on the first day of spring. Usually, the
newscaster will make some vague mention about how this works, but it is rarely
specific, and never holds up to too much scrutiny. You can actually balance an
egg on end any day of the year if you have a steady hand and enough patience.
#78 - Astrology is able to predict the future.
Historically, astrology and astronomy were once considered the same area of
study. They split apart after the 18th century to become a legitimate science
(astronomy) and a pseudoscience (astrology). Astrologists claim they can divine
future events and psychological happenings from the position of celestial objects
(mostly planets). One key problem to the theory of astrology is that practitioners
consider the Universe to be static when it is, in fact, dynamic. Astrological
predictions are only accurate by chance and often contain such vague
information that it could apply to any human being.
#79 - A scientific theory is just a guess.
In scientific usage, a theory does not mean an unsubstantiated guess or hunch,
as it can in everyday speech. A theory is an explanation or model based on
observation, experimentation, and reasoning, especially one that has been tested
and confirmed as a general principle helping to explain and predict natural
phenomena. Any scientific theory must be based on a careful and rational
examination of the facts.
#80 - The Great Wall of China is the only manmade
object on Earth visible from the moon.
Apollo astronauts reported that they were not able to see any manmade object
on Earth from the moon. The Great Wall is visible from a low orbit but so are a lot
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of other things. Cities, dams, fields and ships can all be seen from a low orbit as
well.
#81 - People only use ten percent of their brains.
The brain is an incredibly complex organ.
Unless a person has serious brain damage
where parts of the organ have actually died
or deteriorated, the whole brain is being
used. It is unclear where this notion of ten
percent came from. If the whole brain
wasnʼt active, you would not be able to
move your arms, remember a name or see
the car in front of you – or do all of them at
the same time.
#82 - Going out in freezing
weather increases your chance
of catching the common cold.
There is usually an increase in colds during the winter than during the summer
but it is not because of exposure to the chilly temperatures. When the weather
outside is frightful, people tend to spend more time indoors, increasing their
exposure to each otherʼs germs. The air in winter is also drier than in the
summer. The dry air reduces nasal mucus and the bodyʼs capability to expel
germs.
Physics
#83 - There are seven colors in a rainbow.
ROYGBIV is often taught as a way of remembering the colors of the rainbow.
However, there are a large numbers of distinct colors in a rainbow and there is no
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divider between them. For example, the area between the green and yellow area
of the spectrum is a gradient between those colors.
#84 - We are using up the world’s energy.
According the first law of thermodynamics, energy cannot be created nor
destroyed. Therefore, no matter what we do the total amount of energy in the
universe will remain the same. Chemical energy stored in fossil fuels is released
when they are changed or broken down by some conversion device. For
example, we use a conversion device (gasoline engine, diesel engine) to change
chemical energy into thermal and mechanical energy, to make a motor vehicle
move.
#85 - Heat can only rise.
Heat itself actually doesnʼt rise or fall since it is energy rather than matter. When
we say that heat rises, we are usually referring to warm air. In order for that air to
warm up, the atoms and molecules have to gain energy and increase their
speed. As they speed up, they spread out and lower the
density of the air. Since hot air is less dense, it will “rise”
above the denser, cooler air.
#86 - Liquids rise in a straw because of
suction.
The liquid in a horizontal straw will not rise unless you
suck but the inactivity is not because of a lack of
suction. The water accelerates because of net force
created by a pressure imbalance at the two ends and is
pushed along by the waterʼs own weight. Sucking
causes the pressure imbalance that allows the weight of
the water to push the liquid upwards.
#87 - Gravity cannot exist without air.
When we refer to gravity, we mean the gravitational
force that exists between two forms of mass. The only
factors that figure in to determining this force are a
gravitational constant, the distance between the centers of gravity of the masses
and the masses themselves. Air is not a necessary component in this equation.
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#88 - For every action, there is an equal and opposite
reaction.
Yes, this is what Newton said but it was not what he meant. The term “action” has
changed meanings somewhat since the laws were translated into English from
Latin. What he meant was “for every force, there is an equal and opposite force”.
For example, when you take a step you are putting force down onto the Earth.
The Earth pushes equally back at you.
#89 - Gravity is selective and acts differently (or not at
all) on some matter.
There is an equation that will determine the gravitational force between any
forms of mass. Gravitational force= (G * m1 * m2)/(d^2) where G is the
gravitational constant, d is the distance between the centers of gravity of two
masses and the m1 and m2 are the masses of the objects whose force you want
to know. This equation is the same no matter what masses are being put into the
m1 and m2 slot. Gravity acts in the same way on all matter. The results of the
equation only vary because of mass or distance variations.
#90 - The kinetic theory does not really explain heat
transfer.
Kinetic theory states that the temperature of a substance (or body) is determined
by the average internal energy of its particles. The addition of heat increases this
energy. Heat energy transfers the internal energy into another system or
substance. When two substances come into contact with each other, the
substance that is more “energetic” will lose some of its heat to the substance that
is less energetic.
#91 - Expansion of matter is due to expansion of
particles rather than to increased particle spacing.
Kinetic theory tells us that the introduction of heat to a system increases the
movement of the particles within. As the particles speed up, they separate to give
each other room to move. Heating a substance or body will cause the particles to
spread out and the body to expand.
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#92 - An object at rest has no energy.
An object at rest has what is called potential energy. This is energy stored within
the system that can be converted into or used to fuel other forms of energy, like
kinetic. Energy cannot be created or destroyed so when an object comes to rest
the energy it had in motion still exists.
#93 - The only type of potential energy is gravitational.
Gravitational is one of the types of potential energy but not the only one. There
are also elastic, chemical, electrical and thermal potential energies. Elastic
energy relates to elastic objects that are being compressed or made tense.
Chemical potential energy relates to the arrangement of atoms and molecules,
often due to chemical bonds. Thermal potential energy is the sum of the average
kinetic energy of random motion of the particles that compose the object.
#94 - There is no relationship between matter and
energy.
Remember that old equation E=mc2? It is the mass-energy equivalence formula.
Mass-energy equivalence is a concept in physics that states that any mass has
an associated energy (and vice versa). The E in the formula is the energy
equivalent to the mass, the m the actual mass and c is the speed of light in a
vacuum. The squared c is in there because it acts as a converter between the
units of mass to the units of energy.
#95 - Velocity is another word for speed. An object’s
speed and velocity are always the same.
Speed refers to how fast an object is moving with a high speed meaning fast and
a low speed meaning slow. Velocity is the rate at which an object changes
position. What is the difference? Let us look to a race car for an example. A race
car drives forward at a speed of 150 miles per hour then stops and reverses its
path (at the same speed) back to its starting point. The car was moving at a very
high speed but achieved zero velocity. That is because it retraced its path back to
the starting point.
#96 - There is no gravity in space.
This is probably one of the most commonly held scientific misconceptions. The
largest argument for the truth of this theory is that the astronauts can float around
weightlessly in their shuttle. This is not due to a lack of gravity. Space shuttles
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are essentially a falling container that also moves sideways rapidly in a curved
path parallel to the Earth that keeps it from hitting the ground. If you go skydiving,
you will experience a similar feeling of “weightlessness”. It does not mean gravity
has kicked off. The gravity in outer space is actually pretty strong. Three hundred
miles into space, you would only weigh about fifteen percent less than you do
standing on the solid ground.
Temperature
#97 - The temperature of an object depends on its size.
Does a cup of boiling water have a higher temperature than an iceberg? Yes,
obviously it does and the iceberg is much larger. Temperature is a reflection of
the amount of heat that a substance is transferring outwards. This heat is caused
by the excitement of particles in the material. The more excited the particles are,
the more heat that is generated. Size is not a factor.
#98 - Objects that readily become warm are good
conductors of heat and do not readily become cold.
Heat transfers from areas of high temperature to areas of low temperature. When
a warm object (A) comes into contact with an object with a lower temperature (B),
the heat moves from A to B. When B becomes warm enough that it is at a higher
temperature than something it is in contact with, the heat leaves B for the cooler
grounds. A good conductor of heat warms and cools readily because it, by
definition, allows the heat to move through quickly.
#99 - The bubbles in boiling water contains air.
The bubbles in boiling water (or
any other liquid) are the gaseous
form of water trying to be
created. As the water is heated,
the particles begin to move
around faster with the eventual
goal of becoming vapor. The
liquid does not go from liquid to
gas in one swift step. The gas
that is slowly being created is
less dense than the water it is
forming in and will rise to the top.
It typically starts from the bottom
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of the liquid because that is usually where the heat source is. The less dense gas
rises through the water toward the top.
#100 - Boiling is the maximum temperature a substance
can reach.
A boiling point is the temperature where the liquidʼs vapor pressure is equal to
the pressure surrounding it. When we typically refer to boiling points, they are
those calculated with the pressure of the lab air around it. But different pressures
create differing boiling points. There are an infinite number of boiling points for
any substance since there are an infinite number of pressures that could be
around it.
#101 - Hot objects are red and cold objects are blue.
As a convention, hot objects are often colored red and cold objects are colored
blue. However, when we look at stars for instance the hottest stars are blue in
color and red stars are much cooler. You can see this in a blowtorch flame as
well the hottest part is the blue flame.
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