This is a good demonstration to show to kids at home or at a school.
What you need:
- Plastic syringe (I used a 12mL monoject. One can buy them cheap in large or small quantities on amazon or ebay.)
- Hot tap water, at around 125F
- Cup for the water
- Optional: Thermometer
Step 1: Pour water into cup
Stick a thermometer into it if you like. But don't take too long, or the water will cool off too much.