Active cavity radiometer

Hey kiddo! Do you know what a radiometer is? No? Okay, well a radiometer is a scientific instrument that helps scientists measure the amount of energy that comes from the sun or other sources.

Now, an active cavity radiometer is a special kind of radiometer that is used to measure the energy that is given off by objects that are really hot, like the sun or even really hot gases.

How it works is, the active cavity radiometer has a special "cavity" in it that is like a tiny room with really shiny walls. The cavity is filled with a gas that is really good at absorbing energy from the heat source that the radiometer is trying to measure.

So when energy from the heat source enters the cavity, the gas inside it starts absorbing it. This causes the temperature in the cavity to go up. The radiometer has a special thermometer that measures the temperature change in the cavity.

Then, the radiometer calculates how much energy was absorbed by the gas in the cavity based on the temperature change, and it can give scientists really precise measurements of the energy coming from the heat source.

Isn't that cool? Active cavity radiometers help us learn more about the energy that comes from really hot things in the universe.