ELI5: Explain Like I'm 5

Pyrometric cone

Okay kiddo, a pyrometric cone is a little cone-shaped piece made out of clay that people use to figure out how hot something is.

Now, let's say someone is using a big oven to make some pottery or glass. They want to make sure the oven is hot enough for the stuff to turn out good, but not too hot or it could break or melt. So, they put a few pyrometric cones near the things they're making in the oven.

As the oven gets hotter and hotter, the cones start to bend and melt. Each cone bends and melts at a different temperature, like one might start melting when it's 1,800 degrees Fahrenheit and another might start melting when it's 2,200 degrees Fahrenheit.

The person can then see which cones have bent or melted and know exactly how hot the oven is. It's kind of like a thermometer, but for really, really hot stuff!