What is the difference between conductor ans insulator?

Answer 1

This question can apply to either electricity (electron flow) or heat (thermal energy transfer).

Let us start with electricity:

An insulator exposed to a voltage will not let electrons flow (will not let current flow) until a very high voltage is applied, at which point the insulator breaks down (changes composition) and allows a current arc.

A conductor exposed to a voltage will allow electrons to flow and the current flow will be roughly proportional to the applied voltage.

Now, let us go to heat:

An insulator resists the transfer of molecular vibration energy, but what energy is transferred is roughly proportional to the temperature differential.

A conductor allows the transfer of molecular vibration energy and the transfer is roughly proportional to the temperature differential.