Magnetic Diving Board

What if I told you that I built an apparatus that does just that? I refer to it as a microscope, simply because it takes images of very tiny objects. It is not, however, a microscope in the often-used sense of the word: I don’t look through a set of lenses to focus on the object of interest.

Rather I measure the magnetic forces between the sample I am studying and a small magnetic lever. The lever is like a really small diving board. Really small. Imagine a diving board as long as a human hair is wide. That’s just about right.

Just as a diving board bends due to the force of a diver’s weight, this lever will bend when it experiences a force. For example, by placing a tiny magnet on the end of the lever, I can detect magnetic forces from a nearby sample. Since opposite poles attract and like poles repel, the lever can sense if the sample is magnetic simply by bending.

Because it’s so tiny, the lever can sense very small forces. How small? Consider the mass of a feather – about 1 gram. Imagine it resting on your hand. Not much force certainly, but still perceptible: you can feel some small amount of pressure on your fingertips. This tiny lever can detect forces one trillion times smaller than that. If I were to rest a single red blood cell on the end of this lever, the bending would still be dramatic.

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