system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: When they say “we got 2 inches of rain today” how much rain does that equate to?

When I look outside, I see a lot of water on the ground, but it’s obviously not uniformly 2 inches deep. Is there another way to explain this? How long could I take a shower using the water that fell from a rainstorm that left 2 inches of rain, for example?
gpt
If you put a container out, then the container would fill up with water, two inches from the bottom.

Obviously it won't be exact, but the reason you don't see it on the ground is because water seeps into the ground and runs along it. If you captured it in a container you would see the two inches.