system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do MRI machines work?

I've tried reading the Wikipedia article and get lost having to read a separate article on _every_ term used in the info.
gpt
Really oversimplified explanation:

1. suspend body in really strong magnetic field, forces water molecules to line themselves up in specific direction
2. at same time, zap water molecules in body with a radio wave, causes them to wiggle against magnetic field direction
3. wiggling water molecules give off their own radio waves, slightly different for each kind of tissue. Record it all & use computer to reconstruct 3D picture of it.