1. Thermal Expansion

2. Expansion Many substances expand when heated
When heated, the particles (atoms or molecules) in a substance vibrate more
This means they need more space
So the substance expands
Heat

3. Important note! The particles in a substance do not expand themselves!
Heat
Particles are the same size

4. Contraction The opposite happens when most substances are cooled
The particles vibrate less
They need less room
The substance contracts
Cools

5. Thermal Expansion There are 3 stations around the room.
Read the instructions/complete the task/answer the questions at each station.
You may go around in any order and will have 4 minutes at each station
You must fill in the worksheet for each station and move on immediately when told to

6. Additional Questions
Different materials expand by different amounts for a given temperature change. Considering this, explain why steel can be used in concrete to reinforce structures
Explain in detail how hot air balloons work