Heating Metal Ring
If you heat a metal ring equally on all sides, will the hole in the middle
increase in size, decrease, or stay the same?
The hole in the middle will increase in size.
During the 1800's blacksmiths took advantage of this to fit the metal rims on wooden
wagon wheels. When they were heated the size of the hole expanded and they would fit over
the wheel. They would then cool and contract, holding the spokes in compression and
strengthening the wheel.
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Update: June 2012