How does an electrical current passing through a piece of wire effect its heat?
Current is the flow of charge. It is the flow of delocalised electrons. Whenever a piece of wire has a voltage applied across it, these delocalised electons flow from the negative terminal of the battery to the positive terminal. As they do so, they gain energy and accelerate. However, they collide with the positively charged metal ions which are vibrating about their mean position but not free to undergo translational motion. The “free” electrons lose energy and decelerate whilst the ions gain internal energy. On the macroscopic (larger) scale, this can be seen as an increase in temperature. Therefore, the greater the magnitude (size) of the electrical current, the higher the temperature of the wire.
