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.
Step 2: Put Water in Syringe
Step 3: Boil the Water!
Then gently release the syringe. You should notice that everything returns to more or less how it was before the experiment (maybe with a little bit more air, if some leaked in).
It should also boil if you hold the syringe vertically. But then you or your audience might worry that the bubbling is not boiling, but it's just air leaking in and around the piston.
If it doesn't boil, try using less water. Or hotter water. Or alcohol (e.g., heated by putting a small cup of alcohol in a larger cup of hot water).