system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do Microwaves and Oven Doors Have Small Dots on Them?

It seems that the microwaves have small dots on the door because of radiation, but with an oven it is just heat, correct? I am wondering why oven doors have these small dots, hindering your view of the inside.
gpt
Those aren’t dots on the door of a microwave oven, those are holes, in a thin layer of metal. An interesting thing about radio waves, microwaves, and light—it’s all the same stuff, called the Electromagnetic Spectrum—is that the waves cannot “shine” through holes that are smaller than the length of the wave. Microwaves are several centimeters long, *much* longer than the diameter of the little holes in the metal screen in the microwave oven’s door. But visible light waves are incredibly tiny, about a billionth as long as a microwave. So the light in the microwave oven can shine through the holes just fine.