50 Dangerous Things (You Should Let Your Children Do): Boil Water in a Paper Cup

boil water paper cup

Task: Boil water in paper and watch two seemingly incompatible elements – fire and water – coexist!

 

Requires:

  • Gas or electric stove (sadly and inductive cooktop won’t work)
  • Paper cup (must be unwaxed)
  • Water

Possible Hazards: 

  • Burns
  • Fire
  • Setting off the smoke alarm

How It All Went Down:

Boil water in a paper cup? Impossible, you say! I didn’t believe it either, but we had to try.

This was the first task we’ve encountered where I was legitimately worried that someone or something would get hurt! I had visions of flaming paper and torrents of boiling water spewing out at us. If you’re a little concerned as well, it’s a good idea to have a plan in place before starting. Make sure your cup is stable on your stove. If it’s tippy or doesn’t want to stand upright, wait to try until you’ve found a better cup. Have some tongs and a pan nearby in case you need to move the cup off the burner quickly.  Now on to the fun …

Fill the cup 3/4 full with water. Place it on the hottest part of the burner (over the flame or on the heating coil). Turn the burner on high and wait for the water to boil.

It takes longer than you think, and we were sure that our cup was going to burn or disintegrate before the water boiled. The bottom of the cup got very black … but it never caught on fire before the water boiled! How is this possible?

Water boils at 212°F … but paper doesn’t actually burn until close to 500°F. And while the water is (technically) very hot, compared to a flame it is much cooler.  Notice the spots on the cup that actually begin to burn – the very bottom edge and the top 1/4 of the cup – are the parts of the cup not directly touching the water.

50 dangerous things boil water
Once the water boils, you can either turn the heat off and VERY carefully lift the cup into a pan with tongs, or you can boil away the water until you’re just left with a charred, wet piece of paper. We quit while we were ahead (i.e. no flaming pyre or boiling water geysers) and turned off the flame. It was all over in a matter of minutes, but it’s something we won’t forget about for a long time!

You can read about the rest of our experiences with 50 Dangerous Things. Inspired by Gever Tulley’s book 50 Dangerous Things (You Should Let Your Children Do).

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