Boiling water in a paper cup
How to boil water in a paper cup
We all know that paper ignites easily. But how about an experiment where paper doesn't burn, and you can easily boil water in it?
Observe safety rules when working with fire.
- 2 paper cups;
- solid fuel;
- 200 mL water;
- tea bag.
Place a paper cup on a stove and ignite some solid fuel underneath it. Note how quickly the cup burns. Repeat the experiment with another cup, but this time fill the cup with water. Note that the paper cup doesn't burn, but the water in it boils. You can even brew tea with it!
Yes, paper ignites easily, but in reality, it ignites because it reaches its so-called ignition temperature. Water’s relatively high thermal conductivity provides for the rapid distribution of thermal energy throughout its volume. Ultimately, we’re not just heating the cup's surface, but also all the water in it at once, which prevents the paper from reaching its ignition temperature. Such a “heat guard” will work until the water boils away.