system
Given the following post, respond as if you're commenting on Reddit:
human
If I heat a metal washer, as the metal expands does the diameter of the "inner circle" increase or decrease?
gpt
It will increase. You can imagine it as a sheet of metal with a circle drawn on it. If the metal expands, the circle grows. A hole in the metal would grow too. This effect is actually used occasionally to fit pipes together. One is heated so it expands, slipped over the other, and when it shrinks, it clamps around the other and is fixed really tight without glue, welding or screws.