Peeps go BOOM!

Now, we all know that when you nuke a Mashmallow Peep, they expand and grow gigantic.

But what I’m wondering is why does that happen? I know the same thing happens when you put a mashmallow in a vacuum, so are the two related?

Yes, they’re related; marshmallows are made by whipping air into the base, and that air will expand if you drop the exterior pressure (vacuum) or increase interior pressure (heating – PV=nRT).

When I last nuked a peep, it looked more like it was boiling than just growing. If it was boiling, and not just growing, it’s because you can boil anything by either raising the temperature or lowering pressure.