Penny Statue

How large of a sculpture could you make from melted-down pennies? -Myself

Today I'll be sharing a question that I considered myself: how large of a statue of a person could be made from melted-down US pennies?

While one might think of a penny as a disk, it is technically cylindrical. (OK, technically it's not cylindrical due to the relief images on both sides and whatnot. But that doesn't matter.) The diameter of a penny is 19.05 millimeters and the height of a penny is 1.52 millimeters.[1] From this, it is apparent that the volume of a penny is 285.02 cubic millimeters. So next I needed to find out how many pennies are in circulation. The answer (wait for it):  200,035,318,672.[2]

Given this, the total volume of all pennies currently in circulation is 57 trillion cubic millimeters, or 57,014 cubic meters. That is a lot of cubic meters.^{[citation needed]} It would be enough to fill up 57 Olympic swimming pools and still have enough to fill 14 refrigerators.[3] I love Wikipedia's "orders of magnitude" lists. The average height of an American male over 20 is 69.3 inches.[4] The average width of a human is 18 inches and the average...um...length? thickness? depth? of a human is 9.5 inches.[5] Thus, a person's volume is 11,850.3 cubic inches, or 0.194 cubic meters. Admittedly I fudged this a bit since people aren't rectangular prisms^{[dubious--discuss]}, but it's close enough.

The pennies have a volume 293886.5979 times that of a human. The cuberoot of that is about 66.48, so the statue would be 66.48 times taller, 66.48 times wider, and 66.48 times deeper than life-size. Plugging in the numbers shows that this statue would be 384 feet (117 meters) tall, 100 feet (30 meters) wide, and 53 feet (16 meters) deep. In other words, this statue would be large enough to rank among the largest statues ever built, but not large enough to blatantly defy reality.

Derived from this diagram, created by Jdcollins13. Image is licensed under the CC-BY-SA.

(The statue made of pennies is not anatomically accurate or precise)

With the math out of the way, let's turn to the physics of this statue.

These days, pennies are mostly zinc and the density of zinc is 7.140 grams per cubic centimeter and thus 7,140 kilograms per cubic meter according to Theodore Gray's The Elements. With a volume of 57,014 cubic meters, the statue would have a weight of 407,079.96 metric tons. That's a manageable weight, since many structures that size have been built. For instance, the Great Pyramid of Giza is nearly ten times heavier.[6]

This would cause quite a bit of pressure on the feet of the statue. Some source[7] says that the average 19 year old male foot is 26.15 centimeters long. I also estimate based on a chart here that the typical male foot is 10 centimeters wide. Thus, the area of a both human feet combined is 261.5 square centimeters, or 0.02615 square meters. The statue's feet would have a combined area of 1155.72 square meters. Thus, the pressure that the statue would exert on the ground it is standing on would be 352,230 kilograms per square meter, or about 3.453 megapascals. I suspect this may cause some problems, but they could probably be alleviated by putting the statue on a large concrete base.

In case you want to try this, just be warned that it would be pretty expensive (and apparently illegal[8]). The cost of the pennies would only be part of the cost of building the statue, since you'd have to melt the copper and shape it as well.