Temperature

This demonstration illustrates the temperature dependence of resistance. The effect is caused by the fact that the electrons moving through the wire collide with vibrations (phonons) created in the material by thermal noise. At lower temperatures this will happen less, and thus the resistance goes down. In semiconductors and insulators an opposite effect occurs, where resistance decreases with temperature due to the lowering of the Fermi level, and thus less electrons being in the conduction band.