and Experiment
Experiments
with
and
Raintree
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Contents
Why Experiment?.............................................. 4
What Is It?.......................................................... 6
Experiment 1: Belt-Busting
Balloons................... 8
Freezing and Melting....................................... 10
Experiment 2: Pool
Party.................................. 12
Evaporation and Condensation........................ 16
Experiment 3: Weather
In a Jar....................... 18
Heat on the Move............................................ 22
Experiment 4: Ice
Cream Emergency!.............. 24
Plan Your Next Experiment.............................. 28
Glossary........................................................... 30
Find Out More................................................. 31
Index................................................................ 32
Some words are shown in bold, like this. You can find out
what they mean by looking in the glossary.
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Why E
Where do clouds come from? Why do dogs pant? How
does rock turn into lava? What makes chocolate so
delicious to eat? You can answer all these questions
by investigating what happens when you heat or
cool materials!
Scientists ask questions like these. They find the
answers with the help of experiments. An experiment
is a test that has been carefully planned to help answer
a question.
Get your ears, eyes, nose, and hands ready! You’ll need to observe your
experiments carefully and record what you see, hear, smell, or feel.
4
IS IT A FAIR TEST?
Most experiments involve
changing something to see
what happens. Make sure
you only change one thing,
or variable, at a time. Then
you will know that it was the
variable you changed that
made the difference. This is
called a fair test.
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The experiments in this book
will help you to understand
how heating and cooling
affects materials. You’ll learn
how to work like a scientist,
and have lots of fun along
the way!
Follow these steps to work
like a scientist:
Ask a question.
Come up with an idea to test.
Plan an experiment.
What will you change?
What will you keep the same?
What will you measure?
Make a prediction.
Observe carefully.
ADU
LT
WARNING! Very hot
HELP
or cold things can be
dangerous. Ask an adult to
help you plan and carry out
each experiment. Follow the
instructions carefully. Look out
for this sign.
Work out what the
results mean.
Answer the question!
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What Is It?
Everything in the world is a solid, a liquid, or a gas. These
are called the three states of matter.
ADU
HELLPT
You can see water in all three states in the same
place. Ask an adult to heat a pan on an oven burner.
Use a wooden spoon to put an ice cube in the pan.
Watch as the solid ice changes into liquid water and
then into steam (a gas).
gas
solid
liquid
Solids, liquids, and gases behave differently (they have
different properties). Some of the properties are listed
in the table on the next page. Use it to help you decide
whether the things around you are solids, liquids, or gases
(or a mixture of these).
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Solid, liquid, or gas?
Solid
Liquid
Gas
Stays in one place; easy to hold
and control
Runny; hard to hold and control
because it flows downward
Flows easily; escapes if it’s not
trapped in a container; hard to
control
Keeps its shape
Changes its shape; spreads out to
fill the bottom of its container
Completely fills its container and
take its shape
Always takes up the same amount Always takes up the same amount Spreads out to fill a container
of space (volume stays the same) of space (volume stays the same) (volume can change)
Can be cut or shaped
Can be poured easily
Can be compressed so it takes up
less space
Real WORLD science
Liquids can be poured. Small pieces of a solid can be
poured too, but they form a pile instead of a puddle.
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EXPER ME T
Belt-Busting Balloons
What happens when you heat or cool a gas? Let’s trap
some air (a gas) inside balloons and find out.
EQUIPMENT
• Three balloons
• Balloon pump (or strong pair of lungs)
•Freezer
• Toilet paper
•Marker
•Tape
• Glass jug or bowl
• Hot water from a sink faucet
Method
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1
Blow up and tie the balloons.
2
Wrap a thin “belt” of toilet
paper around the fattest
part of each balloon.
Stick the ends together,
making each belt as tight
as possible. Number the
balloons
3
Put balloon 1 in a freezer.
Leave balloon 2 in the room
where you blew them up.
Ask an adult to fill the jug twothirds full with hot water from the
sink faucet. Carefully place balloon
3 on top of the jug and hold it in
place. What happens?
5
Look at the balloons after 10
minutes. What has happened to
each balloon? What has happened
to each belt? Record your results.
6
Draw a table to record your results.
Where
What happened to the balloon?
What happened to the belt?
Balloon 1
Freezer
Balloon 2
Room
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ADU
HELLPT
Balloon 3
Over a jug of hot water
IS IT A FAIR TEST?
You should only change one thing—the temperature of the
balloons. Everything else should stay the same. How can you
make sure each balloon starts with the same amount of air?
Conclusion
When a balloon was cooled, its belt got looser. When a balloon was
heated, its belt got tighter and broke. The balloons were tied tightly,
so no air could escape or get in. They changed size because heating
air makes it expand, and cooling air makes it contract. The air that
stayed the same temperature did not contract or expand, so the belt
stayed the same.
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