What Am I Riddles

Question: What can you see but not hear?

Question: A thousand wheels, but move I do not.
Call me what I am, call me a lot.

What am I?

Question: The more of me you have, the longer your life.
The more of me you have, the less you have left.

What am I?

Question: I'm number three.
But I'm not a number.
I'm hot and cold at the same moment but not at the same time.
I'm number three.
But I'm not a number.

Who or what am I?

Question:

Take me for a spin and I'll make you cool,
but use me when it's cool and you're a fool.

What am I?