Temperature measures the average motion of atoms and molecules in a material. A higher temperature indicates that atoms and molecules have more energy. They also are moving or vibrating faster. To understand how temperature affects electrical resistance, consider the two types of charged particles inside an atom: negatively charged electrons, whose motion generates current; and positively charged protons, which are 1,800 times heavier. Because electrons are much lighter, they don’t require as much energy to move. It takes a lot more energy, or heat, to get protons moving.
Imagine a hallway where half of the population — all of them electrons — travels in the same direction. Meanwhile, the other half — protons — doesn’t have enough energy to move at all. This would represent a cold wire. As the wire heats up, the protons start vibrating. As their motion becomes more random, these protons are more likely to get in the way of the electrons. That disrupts the current flow. As a result, the higher the temperature, the higher the resistance to the flow of electrons — and electricity.
