system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does the burn of putting your leg in hot water seem to come a second or so after it’s been pulled out?
gpt
So there’s ‘two’ nervous systems that usually work together. This is an example of where one takes over first.

- CNS = Brain. It controls the actions you think about so it takes longer to work.
- PNS = No Brain. Controls reflex actions, ones you don’t have to think about, so it’s faster.

The leg in hot water reaction would work something like this:
1. Leg goes into water
2. PNS realises you are in danger.
3. PNS moves leg out of the water because it knows you’re in danger.
4. CNS realises leg is out of water
5. CNS realises leg is in pain and lets the brain know, meaning you only then feel pain.

I hope that’s simple enough, ask any questions if you need clarification.