Thermal Energy Worksheet
Thermal Energy
Molecules and Heat Review
Name: _________________________________
Date: __________________________________
How to Read the Diagrams
Each box is an object. The circles inside are molecules. The numbers inside show how much energy those molecules have!
8
8
8
8
1
Hot water shoots out of the ground. The ground around the water gets very hot. What happens to the molecules in the ground?
a. They get smaller.
b. Their energy increases.
c. Their energy decreases.
d. They disappear.
2
What is the difference between molecules in hot soup and cold soup?
a. Molecules in hot soup move faster.
b. Molecules in cold soup move faster.
c. Molecules in cold soup do not move.
3
What happens to energy when a computer cools down?
a. The energy increases.
b. The energy decreases.
c. The energy stays the same.
4
Joseph puts hot toast on a cold plate. The plate gets warm. What happens to the toast's energy?
a. It increases.
b. It decreases as it moves to the plate.
c. It stays the same.
5
Cold tea is poured into a glass. The glass gets cold. What is happening to the energy of the glass?
a. The energy is decreasing.
b. The energy is increasing.
c. The molecules are moving faster.
6
Two pipes are touching. The Front Pipe is hot, and the Back Pipe is cold. What will happen after they touch for a while?
Front Pipe (Hot)
100
100
100
100
Back Pipe (Cold)
20
20
20
20
a. Both will reach the same energy.
b. The hot pipe stays at 100 energy.
c. The cold pipe gets colder.
7
Which bottom gear will be cooler after touching the hot top gear?
Set A (Small)
80
80
40
40
Set B (Large)
80
80
40
40
40
40
a. Set A bottom gear.
b. Set B bottom gear.
8
Why does a big object take longer to heat up?
a. Heat is shared between many molecules, so each gets less.
b. Big objects lose energy faster.
9
Written Challenge: The Warm Plate
A chef puts a hot metal lid on top of cold food. Explain why the food gets warmer. What happens to the molecules?
10
Which object is the hottest? (Circle one)
Object A
10
Object B
30
Object C
50
Explain how you know:
Thermal Energy Answer Key
Thermal Energy Key
Answer Key (Teacher Resource)
1. Ground temperature increases when hot water touches it.
Answer: b. Their energy increases.
2. Difference between hot soup and cold soup molecules.
Answer: a. Molecules in hot soup move faster.
3. Energy when a computer cools down.
Answer: b. The energy decreases.
4. Hot toast on cold plate energy change.
Answer: b. It decreases as it moves to the plate.
5. Cold tea poured into a glass.
Answer: a. The energy is decreasing.
6. Pipes touching for a long time.
Answer: a. Both will reach the same energy.
7. Which gear will be cooler (Set A vs Set B).
Answer: b. Set B bottom gear.
8. Why big objects take longer to heat up.
Answer: a. Heat shared between more molecules, each gets less.
9. Written Challenge: The Warm Plate
Key Points: Energy moves from the hot lid to the cold food. Food molecules gain energy and move faster, making the food warmer.
10. Hottest Object
Answer: Object C (50 energy).
Explanation: Object C has the highest energy number (50). More energy means the molecules are moving faster and the object is hotter.
