Diamagnetism, the Clueless Explanation

Diamagnetism, ferromagnetism, and paramagnetism

Opera singers aren't multilingual: even though they sing in multiple languages – French, German, Italian... – in some (or all) languages they've had to learn unfamiliar words' pronunciations phonetically. We often catch our DotD candidates trying to do the same thing in a written form, but when we inspect their content we see that they've merely thrown unfamiliar words at the page in semi-coherent order so that they don't really mean much. One of our favorite examples is serial dumbass Joan Whetzel, who we found fumbling through the terminology in an old eHow.com post (now at Sciencing.com) titled "What Materials Do Magnets Repel?"

Three cheers for Joan for somehow discovering the word "diamagnetic," which describes substances that not only aren't attracted to magnets (ferromagnetic), they form their own opposing magnetic field when exposed to a magnetic field. Interestingly enough, diamagnetism is pervasive: wood, paper, glass, and even the human body all exhibit it. Still, Joan manages to name only a few diamagnetic substances:

"Other than water, materials with the strongest diamagnetic force are carbon graphite [sic], bismuth and silver."

That "other than water" part is pretty important to have glossed over, we think... Oh, and by the way? there's only one kind of graphite, and it's all carbon. Her source was apparently attempting to distinguish graphite from... diamonds, perhaps? Moving on, Joan's explanation of the reason seems to us a bit... unscientific:

"[Diamagnetic substances] contain only paired electrons spinning in opposite directions around the nucleus, thereby canceling each other out and producing no magnetic field."

We're not gonna touch that, other than to suggest that interested parties go to the wikipedia entry on diamagnetism. Some of Joan's other attempts to sound learned on the matter of diamagnetism include lines such as,

• "Because the diamagnetic effect is dim, it takes two substantial pieces of diamagnetic materials surrounding a small, powerful magnet to repel the magnet, or push it in opposite directions and making it appear to levitate." – A] who ever heard of a "dim" field? and B] there's a lot more to diamagnetism than cute levitation experiments!
• "Narrowly sliced carbon graphite has a negative magnetic susceptibility" – We love it that Whetzel just ran to the thesaurus for a synonym of "thinly"! and there's that "carbon graphite" rubbish again...
• "Carbon graphite is not the same as plain graphite, used in pencils..." – WTF is "plain graphite"?
• "The most readily available form of bismuth is found in shotgun pellets." – Ain't gonna go there, no siree...
• "It expands while cooling, where it can more easily demonstrate the diamagnetic effect." – Again, WTF does that mean?
• "Silver... is the strongest electrical and thermal conductor. It has a low resistance which allows electricity to pass easily through it." – Ummm, Joan? Perhaps you forgot that strong conductivity is the same as low resistivity??? Even though you already wrote about it?

We don't think we could have stomached any more, but – thank heavens – that was the end of it. No levitating frogs, just fragments of some experiments Whetzel found online and attempted to put into a mashup describing diamagnetism (with pretty dismal results). So there you have it, Joan: Dumbass of the Day award number twenty-six: still the champion!

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SI - MAGNETISM