Rubber Discs Under Bottle Caps
If you look under a soda bottle cap you’ll always find a rubber disc. It may seem useless but it’s there for a very important purpose. The rubber disc somehow traps carbon dioxide in so that your soda doesn’t lose its gas.
Rubber Discs Under Bottle Caps
Ridges Around The Edges Of Coins
Dimes and quarters have ridges, but nickels and pennies don’t. Back when coins were weighed to reflect its value crooks would shave off the edges and melt them into new ones of higher value. These ridges helped stop with the tampering.
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Ridges Around The Edges Of Coins
