system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why when touching something really hot we initially perceive it as cold?
gpt
I don't know if it is still there, but there is an interesting demonstration of this phenomenon at the Exploratorium in San Francisco which has been seen by many, many people.

Two coils of copper tubing, one on the left, one on the right, converge in the middle, so that the coils alternate. One carries very warm water, the other very cold. You can hold either one comfortably.

However, you cannot comfortably hold the center, where hot and cold alternate, because it feels like your hand is WAY TOO HOT.