Superconductors

There really is something perfect on Earth. It is a superconductor which has zero resistance and
hence is a perfect conductor of electricity. Lead is a superconductor at liquid helium temperatures of
minus 270 degrees Celsius. You might as well get used to Celsius. Only the Americans use
Fahrenheit.

I once had my own superconductor. It was a metal bar at 4 degrees K. I ran a current through it of 100 amperes and tried to find the voltage across it. I had a very sensitive nanovoltmeter. It could see 10 nanovolts if they were there. I could not detect anything.

One time I saw a magnet levitating piece of liquid nitrogen temperature superconductor. This is the "new" stuff .

Levitation that works:
Just cool a frying pan made of lead down to 2 degrees K and put a strong bar magnet on it. The bar
magnet will see a mirror image of itself in the lead sheet and be repelled hence levitated. It can be
moved about effortlessly.