Magdeburg hemispheres
The Magdeburg hemispheres are a pair of large copper hemispheres with mating rims that were used in a famous 1654 experiment to demonstrate the power of atmospheric pressure. When the…
Drain cleaner
A drain cleaner or opener is a person, device or product unblocking sewer pipes or clogged wastewater drains. The term usually refers to a chemical or mechanical utensil such as…
Mint-made errors
Image by/from By the waysideMint-made errors are errors during the minting process. Groups of coins with distinctive characteristics are known as varieties. The term variety applies to coins with both…
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