I understand how the collisions between positive ions and electrons generate heat when a current runs through a wire. I, therefore understand that as temperature increases, collisions are more frequent, translating into a higher resistance. It then follows that, an increased resistance, due to the fact the electrons can't flow as freely, results in increased collisions and an increase in temperature? In other words, an increased resistance equals a greater heating effect? I ask this because, from my understanding, a large current leads to a heating effect due to more collisions but, doesn't resistance hinder the flow of electrons? I tested this once with a piece of wire. I made the wire very short (very low resistance) and when I turned on the power it was cut in half! Any ideas? Thanks!