You Guessed: grams.

First of all, I should say that I thought the popped corn would weigh the same as the unpopped corn - 72.1 grams, so I was surprised when I weighed the finished bag of corn and saw that it had lost weight.

The hot bag of popcorn weighed 62.3 grams. It had somehow lost 9.8 grams, 14% of the total weight.

Faced with this unexpected result, it was pretty easy to figure out how it happened. The popcorn had been heated to steaming hot temperature, losing water and oil vapor while cooking.

That seemed like a lot of water for a little bag of popcorn, especially since the water is coming out of a bunch of hard popcorn kernels that don't seem to be particularly moist.

9.8 grams of water is 9.8 milliliters of water, and that is about a third of an ounce.

Imagine if all you had to drink was the water you could extract from a huge box of uncooked popcorn kernels.

The bag of popcorn contained one more trick. As the popcorn cooled, its weight increased.

Over the next seven minutes, the bag cooled and the weight increased by 1.5 grams.

I know that hot air rises because it is less dense, but it was neat to watch the density of air increase before my eyes. Another reason the bag of popcorn might have gained weight is that water vapor might have been pulled back into the bag. Who knows?

I don't know everything about science, I just have a scale.