why does a silicone rubber heater heat up when stretched

Silicone rubber heaters are designed to have a certain resistance to electrical current, which generates heat when a current is passed through the heater. When the silicone rubber heater is stretched, its resistive properties change, causing an increase in resistance and a corresponding increase in heat generation.

The increase in resistance is due to the fact that stretching the silicone rubber heater results in an increase in its length and a decrease in its cross-sectional area, which leads to a reduction in the flow of electrical current through the material. This, in turn, increases the resistance of the heater, causing it to generate more heat.

Additionally, stretching can also cause a deformation of the molecular structure of the silicone rubber, which can alter its electrical and thermal properties. This change in the material's properties can further affect its resistance and heat generation, leading to an increase in temperature when stretched.