# Wearable expressionsMarch 28, 2013 6:22 PM   Subscribe

What is the math (physics?) going on in this very cool-looking, equations-as-art necklace?
posted by firstbest to Science & Nature (10 answers total) 2 users marked this as a favorite

One of the people leaving feedback on that page says "This is a unique and interesting necklace. It was too large for me as I'm on the petit size. Also, according to my PhD math friend, the formulas are not real." So there's that.
posted by 4ster at 6:27 PM on March 28, 2013

My husband (physicist) says it is overly stylised and they haven't defined their symbols, but he thinks what it is trying to express is the balance of forces such that all three objects (circles) are at rest.
posted by lollusc at 6:30 PM on March 28, 2013 [1 favorite]

I think if you squint at it, you could possibly say that there is something about rotation and potential energy going on there, but that's a stretch. I think this is gobbledygook and the designer doesn't have much math or physics knowledge.
posted by ssg at 6:35 PM on March 28, 2013 [2 favorites]

Yeah, there's a lot there that doesn't look like real — or at least not conventional — mathematics. The leftmost circle has something which looks like a trigonometric decomposition of a point on a triangle into horizontal and vertical components, and the upright is labeled with a "sin" with something else after it, which is more or less right (the length of that upright should be the sine of the central angle), but the angle itself is labeled "y", which is deeply peculiar, since y would conventionally be the length of that upright, and the angle itself would ordinarily be denoted theta.
posted by jackbishop at 7:02 PM on March 28, 2013

PE is normally "potential energy." Note that the two circles on the right are basically identical, which is sort of weird. They both have f(I), I've seen I as shorthand for an exact integral (as opposed to a quadrature). It's also the conventional symbol for electric current in physics. The notation xji is normally reserved for matrix operations (for example, a symmetric matrix X will satisfy xij = xji). Note quite sure what E ≡ E is supposed to suggest (E is identical to… E?), but E is often just "energy." The expression dℓ(I)/dI suggests that is a differentiable function of the variable I. Script appears in math occasionally, but I can't think of anything it conventionally means, since "length" in vector calculus is usually s. There are also some unlabeled normal vectors (lines with arrows) poking up from the circles.

Put me in the "math-flavored gobbledy-gook" camp.
posted by Nomyte at 7:17 PM on March 28, 2013 [1 favorite]

Yeah, as a professional mathematician I'm going to say that it's cool-looking but more or less meaningless.
posted by number9dream at 7:21 PM on March 28, 2013

The left one seems like someone was trying to do something with the unit circle and trigonometric functions, but didn't understand it.
posted by empath at 8:01 PM on March 28, 2013

I agree that it's been stylized into "gobbledy-gook", but I bet it started life as a force diagram for a pulley. As others have said, PE is potential energy. (Especially since PE is a function of height, or y.) "I" is commonly used for moments of inertia, W for work, and X for distance. I'm guessing ℓ might be length. "E=E" might be referring to the conservation of energy.

Like I said, overall, its still not really saying anything...but I could see this as originally coming from the problem set from a freshman mechanics course.
posted by tinymegalo at 10:14 PM on March 28, 2013

Heya, I'm a physicist, the circle with the angle inscribed in it looks a bit like this definition of the sine function, and like everyone else I'm getting hints about rotations: all of the circles, the use of I for moment of inertia, and it's possible that the subscripted letters are tensors of inertia (a matrix which gives the moment of inertia in each direction).

But apart from that, there's not a lot there that I can see. I'd say it's either so over-stylised it's meaningless now, or just made up pseudo-maths.
posted by Ned G at 6:11 AM on March 29, 2013

Jibberish. But cute! Maybe we should get together in Projects to design and produce a similar necklace with real math. :)
posted by BrashTech at 7:54 AM on March 29, 2013

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