| What makes popcorn pop?
When you pop a kernel of popcorn, you are making an explosion -- you
are making a gas expand very, very rapidly so that the kernel gets blown
inside out.
Each kernel has a hard shell, the hull, that is sealed
tightly. Inside that hull is some starchy material and a
little bit of water.
 When you heat up the
kernel, in hot oil or in the microwave oven or in very hot air, the
water gets heated to the boiling point. But, it is trapped
in the hull and has nowhere to go. Finally, the pressure
gets so high that the hull explodes. The force of
the water that rapidly turns to steam blows up the starch about 40 times
its size!
Good popcorn is about 14% water. In the experiment at the
Carnival of Chemistry, you can learn how much water there is in the
popcorn kernels.
First you weigh some kernels of popcorn. Then you pop them (in
the microwave or in hot air) and weigh them again. Do they weigh
less or more?
If weight is lost where does it go? It is water that is turned
to steam.
Learn more about popcorn:
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