Here are examples of how thermal energy is transferred by conduction, convection, and radiation.

Thermal energy can be transferred by three primary methods: conduction, convection, and radiation. Each one operates differently and in particular circumstances.

1. Conduction: Conduction is the transfer of thermal energy through a substance or between substances in contact with each other without the movement of the substance itself. An example of conduction is when you heat one end of a metal rod and the other end eventually becomes hot. That happens because metal is a good conductor of heat, meaning the thermal energy is passed along from the heated particles to the adjacent cooler particles by direct contact. The rapidly vibrating particles at the heated end increase the vibration of the adjacent particles, and this vibration (and therefore the heat) gets passed along the rod.

2. Convection: Convection involves the transfer of heat by the physical movement of a fluid (which may be a liquid or a gas). For example, when a pot of water is heated on a stove, the water at the bottom of the pot that is in contact with the heat source gets heated first. As it becomes hotter, it becomes less dense and rises. Colder, more dense water then moves to the bottom of the pot to replace it. This creates a circular flow called a convection current, which distributes the thermal energy throughout the pot of water.

3. Radiation: Radiation is the transfer of thermal energy through electromagnetic waves. This process does not require a medium, meaning that energy can be transferred through the vacuum of space. An example of radiation is the heat you feel coming from the sun. Even though space is cold and mostly empty, the energy from the sun travels through space and can be felt as warmth when it reaches your skin.