joke time

[Fireball]

Heads wouldn’t explode. The result of opening the fly zipper (or any zipper) would be the same as removing the helmet. The astronaut would lose consciousness with a few seconds and be dead of asphyxia in about two minutes.

Boru

In high school I volunteered to be part of an experiment in my Chemistry class. Bad idea.  The teacher had 3 fingers missing, allegedly having them blown off making nitro-glycerin.

I put my thumb into a hold in a bell jar, and he turned on the vacuum.  In a few seconds my thumb was double size and it hurt like hell.  It took a while to get my thumb out.

If the decompression occurs all over the body, nothing will explode or bulge out, because the whole body loses pressure (of course there needs some pressure to support blood flow).  If, however, the space suit held pressure in most places, but only some parts of the body were exposed to vacuum, there would 14 psi internal pressure on that tissue, which would cause a lot of damage quickly.

Your chemistry teacher was a complete asshole, and a criminal in this case, to boot. I taught physics for a couple of years, at a private school (thus not needing a credential). The chemistry teacher had a demo where he poured 8M sulfuric acid on sugar. Of course, it's a quite exciting exothermic reaction, but I guess that he poured the acid too fast and the shit exploded. I found out later in the day that his trousers had been destroyed and that he had found a graduation gown somewhere to wear so that he could go home in some sort of decency. Having been trained in hazmat by then, I went up to the grocery store and bought several pounds of baking soda, and went back to the lab and neutralized all the spatter. Then one of the office people and I called the entire 9th grade class' parents to tell them that their kids probably didn't have acid on their clothes, but that they should get a shower and have the clothes washed separately, just in case. The chem prof, upon being told (by me) that I had cleaned up his mess, asked, "So, do you want a medal, or a chest to pin it on?". Stupid fuck.