A bucket made of plastic does not rust like a bucket made of iron. Why?

Wheels are made circular. Why?

Which one of the following is not made of soft iron ?

Why are bells made of metals?

Calorimeters are made of metals not glass. Why?

A spherical shell made of plastic, contains a charge Q distributed uniformly over its surface. What is the electric field inside the shell? If the shell is hammered to deshape it without altering the charge. Will the field inside be changed? What happend if the shell is made of a metal?

The dams of water reservoir are made thick near the bottom. Why?

Explain why the water doesn't fall even at the top of the circle when the bucket full of water is upside down rotating in a vertical circle?

Why connecting wires are made of copper ?