Here you will find scientific terms
that are used in our books as well as definitions of other science words that you may find
helpful. We have tried to make the definitions simple enough for elementary school students to understand so
if a science word you are looking for is missing or confusing as defined here, please
let us know, and we will try to add it or clarify it for you.
Aristotle - Ancient Greek philosopher who was interested
in how things worked. He tried to explain how things
worked without actually doing any experiments.
This made him get some things wrong, for example, how
gravity works. You can learn
more about him by clicking here.
Astronauts - Astronauts are people who travel to outer
space. Sometimes they are also known as
cosmonauts (Russian terminology) or taikonauts (Chinese terminology).
Atmosphere - is the layer of gases that usually
surrounds a planet. For Earth, we call this
mixture of gases air.
Barometer - a device that is used to measure atmospheric pressure.
Learn how to make your own barometer by clicking here.
Conserve - when something is conserved it does not change in value. For example,
when you pour juice from a bottle into different glasses for your friends. Even if the shape and
size of the different glasses change, the total volume of the juice would be the
same as it was in the bottle. The total volume of the juice is conserved.
Density - the amount of something
in a given measurement. For example, if you can fit two basketballs in one box, then the density
of basketball for each box is 2. Another example, if you type 300 words on two pages, then the
density of words per page is 150.
Experiment - A set of steps designed to test a hypothesis.
This usually includes makings observations
and/or taking measurements of the interaction of
objects. For example, you might time how long it
takes for different objects to fall to the ground from a
certain height to see if it takes as long as you thought it would.
Force - A force is a pull or a push. For example, when
you ride a bicycle, you have to push on the pedals to
make the wheels turn. You are using force to make
the bicycle move. Similarly, when you pull a cart
you are using force.
Friction - A type of force that opposes movement.
For example, if you try to push a table to the left side
of a room, the force of friction would be between the
table's legs and the floor towards the right side of the
Galileo - You can learn more about Galileo by clicking
Gravity - is the force created by mass
that attracts other objects to that mass. For
example, the Earth's gravity attracts us to it therefore
keeping us firmly on the ground. Check out the book,
"Why Can't I Jump Very High? - A Book About Gravity" for more
Hypothesis - An educated guess or prediction about what
might happen under certain circumstances. For
example, if you were to drop a feather and a hammer from
the same height at the same time, your hypothesis might
be that the hammer will hit the ground first, or it
could be that they both fall together.
Isaac Newton - is one of the most famous physicist and
mathematician that ever lived. He came up
with Newton's Three Laws of Motion and discovered the
law of gravity. He also invented
a useful advanced way of doing mathematics, called
calculus. You can find out more about Sir Isaac
Newton by clicking
Joule - is a measurement of energy. When you apply one newton of
force over a distance of one meter, your body spends one joule of energy to do it.
kilogram - is a unit of mass.
Mass - The amount of stuff something is made of.
The more stuff something is made of, the more mass it
has. Suppose everything in the world were made up
of marbles. In this case you would be made out of
more marbles than a piece of paper because you have more
mass than a piece of paper.
Massive - Something with a lot of mass.
newton - is the unit of force. If you accelerate one kilogram
of mass at one meter per second-squared, you are applying a force of one newton
Orbit - An elliptical path that satellites and planets
take around a more massive
object. For example, the planets in our solar
system are in orbit around the sun, and the moon is a
satellite in orbit around Earth.
Pressure - is the force applied over a certain area. If the
force applied is much more than the area over which it is applied, the pressure is huge.
If the area, however is much more than the force being applied the pressure is small.
Rate - change of one thing compared to another. For example, when you run, the distance you run
in a certain amount of time is your speed. Another way to say it would be that your speed is the
rate which you run.
Star - is a giant ball of gas in space that creates its own light through a process called
nuclear fusion. The sun is our closest star.
Sublimation - is the process in which a solid object turns directly into a gas without becoming a
liquid first. Dry ice, which is just solid carbon dioxide, goes through this process in
Vacuum - space that is completely empty of everything, including air.
Value - in science value usually is a number that tells you how big or small something is. For
example, a dog usually has a mass that has a higher value than a kitten.
Variables - Variables are things that change in an experiment.
For example, when you plant sunflower seeds in different
types of dirt to see which dirt is best for growing
sunflowers, the variable is the different types of dirt
Volume - tells you how much space something takes up.
X-ray - really high energy light that cannot be seen with human eyes. It is strong enough to pass
through many different materials including the human body. This makes it useful for doctors to
be able look inside you to see if everything is ok with you. For example, if you have a nasty fall
while riding your bike, an x-ray photo of you can show if you have any broken bones.