Living with Thermal Expansion
and Contraction
Objective: Cite examples of how
thermal expansion and contraction
affect everyday objects.
Number from 1-37, single lines.
Using the
pictures of the
world around
us, name two
ways that cause
temperatures to
change.
1. Day to Night
2. Seasons
List the three
main states of
matter:
3. Solid
4. Liquid
5. Gas
3.
4.
5.
6. Most matter
_____ when
heated.
expands
7. Most matter
_____ when
cooled.
contracts
This is true for
every state of
matter.
8. _____ is the only substance that does
not contract with cold or loss of heat.
water
9. Water molecules in crystal form have an openstructured hexagonal arrangement, so water _____
upon freezing.
expands
10. This makes it become less _____.
dense
11. Give an example of when you saw evidence of
water expanding as it froze.
Expansion and Contraction of Solids
People who design
structures such as
buildings and bridges are
very careful about the
materials they use.
12. What would
happen if they chose
materials that would
break when
temperatures change?
A building project will
often require two or
more materials.
Designers would not
choose materials that
expand and contract in
different ways.
13. What would happen
if one material
expanded faster than
another material?
• Think about solid materials you use or see
every day.
• Write down these examples of solids that
expand and contract.
14. Metal frames around windows
15. Hot-water pipes in homes
16.Car Engines
17. Metal lids on jars
18. What happens if your tooth and
filling don’t contract and expand the
same?
19. Do teeth expand and contract?
Some scientists
work on
making new
filling materials.
They want
these fillings to
expand and
contract just
like real teeth.
Building with Concrete
• Engineers use
steel rods to
make concrete
bridges and
buildings
stronger. The
rods help
support the
concrete.
• 20. What
happens if the
steel doesn’t
expand the
same way as
the concrete?
If the steel does not expand at the
same rate as the concrete, the
concrete can crack. Eventually the
building could fall.
• 21. Look at this
bridge expansion
joint. Here is an
enlarged view. Why
would bridges need
these?
• Bridges and
sidewalks are built
in sections. There
are spaces between
the sections called
expansion joints.
Expansion joints
allow steel and
concrete to expand
without cracking.
• 22. What are
the cracks in
the sidewalk
for?
• 23. Would
these cracks be
bigger or
smaller in the
summer?
• Think of
railroad
tracks. They
also have an
expansion
joint.
• 24. How do
you think
this one
works?
This track was
laid in February;
the picture was
taken in August
25. What do you
think might
have happened?
26. Can you think of
a reason that a
pipeline would have
to look like this?
27. Why would it be
made in segments?
Expansion and Contraction of Liquids
• Think about liquid materials you use or see
every day.
• List examples of liquids that expand and
contract:
28. Gasoline in cars
• Better to fill up in
the morning. Gas is
more dense in the
cool morning.
• Never fill up when a
truck is filling the
tanks. The gas is less
dense because it is
full of bubbles.
29. Engine Coolant
Engine coolant doesn’t freeze!
30. Oceans and Lakes
31. Alcohol in Thermometers
• In the last 100
years, the
temperatures of
oceans and lakes
on Earth
increased.
Warmer oceans
and lakes have a
greater volume.
When oceans have
larger volumes,
sea levels rise.
• 32. What effect
might this have on
the world?
Expansion and Contraction of Gases
33. Gases that are heated
will __________ in their
containers.
expand
34. The energy of the gas
particles will _______.
Move faster
The particles of warm gases
hit the walls of the container
more often.
They also hit the walls
harder.
• If the walls of the container are flexible, the
walls expand. If the walls are not flexible and
cannot expand, then the pressure inside the
container increases.
• 35. Which of these two has flexible walls?
A
B
• Think about gases you use or see
every day.
• Write down these examples of gases
that expand and contract:
36. Air in tires
37. Air in a Soccer Ball
38. Air in Balloons
39. Air in an Air Mattress
40. What would happen if those
materials did not expand and contract
as they are meant to?
When cars and bicycles travel, their tires rub on
the road. This makes the tires get hot. The air
inside the tires will expand. If the tires are too
full, they could burst.
Sports balls such as soccer balls are
also filled with air.
41. What happens if you leave a soccer ball out
in the cold?
- the air inside the ball will contract. The ball
will get soft and it will become unusable.
HOMEWORK
• 1. Name two solid structures that expand and
contract.
• 2. Name two liquids that expand and contract.
• 3. What would happen to a bridge that did not
have expansion joints? Explain.
• 4. Correct this statement to make it true: “The
particles in a material ‘get bigger’ when
heated.”
• 5. Identify two examples of thermal expansion
or contraction you have seen or used and
explain how each affects you.