All bodies, regardless of their material or temperature, emit thermal radiation. The higher the body temperature, the more thermal radiation the body emits per unit of time.

Thermal radiation is one part of invisible light that we learned in 8th grade - thermal radiation is infrared light. The generation of heat radiation is related to the heat movement of matter particles, you can read more about it in the following material.

Heat radiation and heat movement

We know that the particles of matter are in constant thermal motion. We also know that all bodies emit infrared radiation, also known as thermal radiation. How are these two phenomena related?

In this first experiment, we heat a resistance wire to glow with an electric current. This way we get a good source of infrared/heat radiation to experiment with.

More precisely, we can make sure of the presence of heat radiation by heating a piece of paper with it.

From the study of heat, we can use the concept of convection to discuss this question. Given that the temperature of the wire is high, convection must occur in any case, and we can feel it when we hold our hand over the wire.

In fact, we can also speak here in the language of light education, because in terms of beam optics, a wire is the same light source as any other that we dealt with in light education. Among other things, heat radiation spreads in a straight line, which is why a shadow appears near the ends of the wire, behind the crocodile terminals.