An electric immersion heater is put at the bottom of a large tank of water. The water next to the heater becomes warm. (i) What will happen to the warmed water next to the heater? Give a reason for your answer.

The warmed water next to the heater will rise. The reason is that warm water is less dense than cold water, which means that warmer water will rise and colder water will sink. This process is called convection current.