Purpose: To determine what percent of a popcorn kernel is water.
Hypothesis: Once popcorn is heated, it will lose some of its water mass to steam and have less mass afterwards.
Materials: This experiment will require a beaker in which to pop the popcorn, popcorn kernels to pop, oil to pop them in, and aluminum foil and a bunsen burner to pop the popcorn with.
1) Fill the bottom of the beaker with the oil, then cover the top of the beaker with aluminum foil. Poke holes in the aluminum foil. Weigh the beaker with oil. Record weight.
2) Add approximately 25-30 popcorn kernels to the beaker. Weigh the beaker with oil and popcorn. Record weight.
3) Place beaker over flame of bunsen burner to pop. Once popped, allow to cool, then weigh beaker with popped kernels.
(Conveniently hotlinked from my friend Steven's blog.)
From these data, we can see that the popcorn kernels lost mass after they were popped, meaning that some of their mass went to the water that evaporated and was captured by the aluminum foil. Precisely, they lost approximately 15% of their mass, suggesting that popcorn kernels are about 15% water.