The technology behind it is based on resistance wire and it functions on a single dimension so-to-speak. A high surge of electricity is required to get it to a specific heat, where it will stay until the thermostat switches it off. 

Like most parts, water heater elements have a finite working life. ... In some cases, mineral sediment collects at the bottom of the water heater tank, encasing the lower element. Forced to work harder, the element eventually fails. You can turn off power to your water heater and drain the tank every few months.