Some time ago I was looking for materials to possibly build a foucault pendulum. Of course the first step is google. There was a site that suggested two old issues of Scientific American, and it happens that we have tons of old Scientific Americans in the store room. I found the two that I needed. I will talk about foucault pendulum in second, but let me show this picture.
This is a device to prevent elliptical motion of the pendulum. Part of it has a ring of nickel. Now for the quote:
“The nickel ring, perhaps appropriately, should have the dimensions of a U.S. five-cent piece, with a 3/16-inch hole exactly in the center. (Do not make the part from a coin; it is illegal to deface U.S. currency.)”
Pure awesome. But, it turns out that this is NOT illegal. This was addressed in a Make Magazine article on making rings from coins. Here is a Lifehacker post on essentially the same thing with all the notes about the legalness of destroying coins. Essentially, it is illegal to deface the coins to make money (i.e. cut off a little of each coin to make money from the metal cut off). Clearly it is not illegal – you see these “smash a penny” machines at museums and stuff.
Finally, here are some Foucault pendulum links:
- Foucault pendulum. This is a pretty detailed site with most of the stuff you would need to know about the foucault pendulum.
- Wikipedia Entry
- How to build your own short foucault pendulum.
There was a whole bunch of other cool stuff I saw in this magazine. Material for a future post.