Why is it that when you look at the sun or a bright light with your eyes closed, your eyelids are red? Is it because of your blood or because of colours being absorbed by red?

Every action has an equal and opposite reaction, so how much force is produced by urination? Could it knock someone over?

Could you launch satellites and perhaps many small capsules from airships to save on all that fuel getting it off the ground?

Why is it that even though I have light brown hair, when I get into the shower or hot spring, my hair turns darker?

When I'm cracking my knuckles back and forth, is it true that it causes arthritis? What's happening when you do this?

I often use silicone sealer, the kind of stuff you put round the bath. The only thing that seems to finish it off into a right angle (ie: right into the corner of your bath so water doesn't drip behind it) is to wet your finger. Over the years I've tried all sorts of things including a piece of round steel, fairy liquid, salt water and everything. But the only thing that really works is to wet your finger and keep running it along. Why does that work?

Why is it that if water freezes at zero, we get frost at three degrees?

In Middle Ages they thought the world was flat. Is the universe flat, or does it just go on and on and on, or is it a certain shape?

My girlfriend and I were talking about flying in a plane and the fact that the higher you go, the colder it gets. How can this be seeing as sunshine and radiation are everywhere?