1. Lesson Starter WRITE IN SENTENCES
Describe what happens to the particles when you:
a) Heat a liquid up
b) Cool the substance back down

2. Lesson 8 – Learning Intention
To learn what happens to solids when we heat them up

3. Aim of the experiment
We know that particles move faster when we give them more energy (by heating them up) Does this make the material (being heated) change in any way?

4. Apparatus Goggles Bunsen burner
Metal ball and ring (or clamp and T bar)
Clamp stand

5. Method Use the clamp stand to hold the ring (or clamp) securely
Check the ball fits through the ring (or the t-bar fits into the clamp)
Light the Bunsen burner and turn it to the warmest flame
CAREFULLY roast the ball (or T-bar) for 1 minute
Now try and see if it still fits- BE CAREFUL
Hold the metal under the cold tap for a few minutes
Check to see if it fits
Turn off the Bunsen and let everything cool down

6. Safety Roasting hot metal is very dangerous
What safety precautions do we need to take?

7. What did you see? Why do you think this happened?
Results
What did you see? Why do you think this happened?

8. Conclusion
When we heat the particles up, we gave them more energy so they moved further apart causing the material to get bigger
This is called EXPANSION

9. Conclusion
When we cooled the metal back down, the particles didn’t have as much energy so couldn’t spread out as much
The material got smaller
This is called CONTRACTION

10. Particles The particles themselves DO NOT CHANGE SIZE
It is the space between them that gets bigger or smaller

11. Expansion and contraction (copy)
When the metal was heated, we gave the particles more energy. This caused them to vibrate faster, move further apart and therefore EXPAND.
The particles CONTRACT when cooled back down because they have lost energy and aren’t vibrating as fast.
The particles themselves do not change size, it is the space between them that gets bigger or smaller.

12. For homework..
Think and write a few sentences on a situation where this (heating causing expansion) would be a problem.