system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why it looks like a rainbow of colors when my phone screen is wet and it's a plain slate of color.

Like white. I got sweat on my phone and many colors show up under the sweat. What is happening here?
gpt
A screen is made up of pixels, and each pixel has three parts-red, green, and blue.

By varying how bright each color within a pixel is, any shade of any color can be made (they usually work in 256 steps of brightness per color, 256^3 is about 16.7 Million colors).

When you get water on the screen, the curve of the drop effectively works like a magnifying glass, and makes the tiny pixels you normally can't see very large. This magnifies the red/green/blue enough that you see them separately, and a rainbow effect happens.