# How do home ovens have hotter or colder zones inside, requiring you to rotate the pan or whatever is cooking. Wouldn’t a small enclosed space have a consistent temperature throughout? And bonus follow up, what sort of degree variation can there be?

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How do home ovens have hotter or colder zones inside, requiring you to rotate the pan or whatever is cooking. Wouldn’t a small enclosed space have a consistent temperature throughout? And bonus follow up, what sort of degree variation can there be?

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Generally it is based on the positioning of the heating elements. For instance: many ovens have the heating element at the very bottom, which is why they say to put frozen pizza on the “middle rack”. While the enclosed space will make the interior MOSTLY the same temperature, there are still fluctuations based on the material being cooked as well as smaller things like how well heat stays inside.

If you shine a heat lamp on something, it will get hot. If you enclose that object in a box it will radiate heat to it’s surroundings to heat the area around it up. As energy is lost in the process of heating the area up, the object will always be warmer than the area.

A small enclosed space with a single source of heat won’t have a uniform temperature distribution; the temperature is hotter near to the active heat source. If you let the oven warm up and condition itself so that the metal walls are hot, the metal walls re-radiate heat passively into the space, creating a more even distribution. If you have a convection fan in your oven to move the air around, the temperature distribution is much more uniform.

Many ovens use heating elements where a significant amount of the energy transfer (particularly before the oven is at full temp) is via infrared radiation, thus the heating pattern looks more like shining a light inside a box – where are shadows and places where more light is direct, and some where it’s mostly reflected, or even relatively dim.

Once the oven is up to temperature, the whole of the “box” of the oven is also radiating heat, making the oven “light” much more uniform.

To add, yes metal walls heating up and all that but also:

Ovens don’t get up to temp and then stay there, it works like this

Oven goes 100% until temp is reached then turns off, oven cools to what ever the lower tolerance then turns back on at full until temp is reached again, over and over heating and cooling