(cross posted on Natural Blogarithms)
The elementary school where my boys attend is hosting a fund raising contest where students bring their change to donate. Instead of accumulating donations to win for their own grade, they are putting their change in other grades canisters. The grade with the lowest weight in donated change at the end of the fund-raising wins. Pretty innovative, I think. The kids seem motivated, so fortunately for the school they are not colluding to all bring nothing which would keep their weights down. Instead they are piling in the change especially those with siblings in other grades.
Strolling through the halls, I overheard a conversation where teachers were wondering if anyone had found out which coins weighs the most so they could give more of those. Of course, that got me thinking. The obvious answer would be that the larger coins like the half-dollar or presidential dollar would be the heaviest.
Although, don’t you really want to have the most weight for your money? Sure, I could put in 10 presidential dollar coins, but which would weigh more, 10 dollars in half dollars, 10 dollars in quarters, or 10 dollars in dimes?
So, of course, I had to know the answer. Checking out the U.S. Mint, I learned the following weights for each of the coins:
1 penny = 2.5 g which means $1 in pennies is 250 g.
1 nickel = 5 g which means $1 in nickels is 100 g.
1 dime = 2.268 g which means $1 in dimes is 22.68 g.
1 quarter = 5.670 g which means $1 in quarters is 22.68 g.
1 half-dollar = 11.340 g which means $1 in half-dollars is 22.68 g.
1 dollar (coin) = 8.1 g which means $1 in a single coin is 8.1 g.
In spite of the larger weights for the larger coins, you are still much better off dumping in those pennies. I did learn a pretty interesting fact though: A dollar in dimes weighs the same as a dollar in quarters which also weighs the same as a dollar in half-dollars. Pretty cool!