This week we did a little popcorn science, the questions being: what happens to the mass and volume of popcorn after you pop it and why does heating kernels make them pop? We measured the mass and volume of a sample of kernels and then threw in some oil (30 ml / 23 g to be exact). We put all the popcorn into a pot with said oil, turned on the stove, waited, and then POP! We took out the popcorn, weighed it, measured the volume, and here's what the kids concluded: The kids predicted the volume would increase and so it did...practically by a factor of 10. The mass, on the other hand decreased a tiny bit.
As for why the heat makes it pop...turns out there's a tiny bit of water inside each kernel, which when heated expands and exerts enough pressure to burst the kernel open. As each kernel "explodes", its volume increases while at the same time allowing a small amount of water to escape, accounting for the slight decrease in mass.
No comments:
Post a Comment