Question

The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?

Answer 1

Plastic or rubber is an insulator. Insulators have tightly bound electrons in their outermost electron shell. So, there are no free electrons and so, they cannot move from one atom to another.

Complete answer:
We all know that plastic or rubber is an insulator that does not allow an electric current to pass through the tools. Rather, charges remain confined to it. The handles of the tools like screwdrivers and pliers used by electricians for repair have the covering of plastic or rubber, for which electric current does not pass through these tools to the body of the electrician.

Now, come to the point of what this insulator is. Materials through which charge cannot move are called insulators. Insulators are also called non-conductors. If any part of an insulator is charged, charges remain confined to that part of the insulator and do not spread all over the body.

The reason behind this is that in insulators or non-conductors electrons are tightly bound to the nucleus – they are not free electrons (they cannot move freely from one atom to another). So, electricity cannot flow through them.

Additional information:
Besides conductors and insulators, there is a third kind of materials called semiconductors, which are neither good conductors nor good insulators. For example, selenium, silicon, etc. They are widely used in electronic circuit elements like transistors, integrated circuits, etc. Again, a few substances can be made to behave as almost perfect conductors at very low temperatures. These are called superconductors.

Note: In an electricity supply system, the transmission wires are joined through insulators, which are non-conductors. But if the wires were directly connected, electricity would have been grounded instantly and there would be a huge transmission loss. In a laboratory connecting wires used for different electrical experiments are wrapped with rubber, plastic, etc. to reduce the chance of short circuit. These are called insulated wires. But always remember that generally no material can be said to be a perfect insulator.