> I wonder why a mirror will switch your left and right, but not your top and bottom. Even if you
> turn it on it's side, it still switches only left and right.

Because your eyes are side by side, not on top of each other.

> I wonder why a Thermo keeps hot things hot and cold things cold. How does it know?

It doesn't. It just stops the heat going where it isn't.

If the contents are hot, the heat stays in.
If the contents are cold, the heat stays out.

> If you put your right hand in ice water and your left hand in very hot water, then put them both in
> water that is at room temperature, it will feel warm to your right hand and cold to your left. I
> wonder why?

Acclimatisation. The nerves in your right hand start pretending everything's hotter than it is, and the nerves in your left hand start pretending everything's colder than it is.

Paul