popcorn lab

This lab was extensively amusing to do. (please ignore the cuss word. it was either me or Timmy and neither of us can remember when we jumped)

Supplies:

1. 100 grams of oil
2. 30 corn kernnals
3. a beaker
4. a bunson burner
5. a striker
6. gas
7. bagged popcorn

Procedure:
First we weighed the beaker. Then added the corn and weighed it again. Each weighed about a gram more/less respectfully. Leigh managed to turn the burner on and we waited for the kernels to reach the appropriate temperature before it began to pop. It was crucial for us not to burn the popcorn (I had a theory that burned popcorn weighs more, where we managed for the most part and then we had to wait for the popcorn to cool down.
WE weighed again (each about weighing a gram and a half each more) and found that the popcorn, popped had more massed being fluffy then actually being a hardened kernel. I thought that was interesting for the most part because i believed it would have lost mass instead of gaining that.

IT raised some questions for me though.
Is this a constant factor with popcorn? What if we tried this with other items that will pop, would the same result happen? It seems like the water from the popcorn had evaporated and that had caused the reaction which was the popping of the kernel. Why would not the oil then rejuvinate the kernel as the water evaporated as it does for human skin?