Thermal noise

Thermal noise is the sound that comes from heat energy. Heat energy is all around us and it is always moving, so it makes noise. Think of it like the sound you hear when you open the oven door. That sound comes from the heat energy that is moving around inside the oven. Thermal noise is the same kind of noise, but it is on a much smaller scale. It's too small to hear, but it can affect things like radios and cellphones.