Bench Press

At Bench Press, we tend to cover new technologies used to solve challenging scientific problems or enhance the quality of science — whether it be electronic lab notebooks, the use of computational modeling, distributed supercomputing, or new nano-sensor technology.

And, while these are all interesting and powerful applications of technology, we oftentimes forget the beautiful simple solutions. Roughly 158 years ago (plus or minus a day or two), Jean Benard Leon Foucault demonstrated a very simple and elegant proof that the Earth rotated on its axis. Of course, by then, I’m sure most scientists, having seen the movement of the stars and the sun in the sky, accepted this, but Foucault gave the first non-celestial visual proof of the earth’s rotation.

He used a pendulum.

A more rigorous explanation of how this experiment works is on Wikipedia, but in short, if you were to hang a pendulum from the North Pole (or the South Pole), you’d expect to see the oscillations gradually move as the planet rotated. It’s not that the pendulum’s rotation is changing (relative to someone from outer space), it’s that the earth is rotating underneath the pendulum. This effect becomes weaker the further away from the poles you move (and Foucault derived a mathematical rule which explains this, as described in the Wikipedia entry).

This brilliant insight led Foucault to invite the scientific community in February 1851 “to see the Earth turn” — hoisting up a massive 62-pound brass sphere with a marker on the end to trace the pendulum’s path as it went back and forth. 

So, yes, we may beam with pride today at our amazing, cutting-edge technology, but I personally am far more impressed (and hope the scientific community is too) by the scientist who needs only an elegant demo/prop to make the same conclusion.

(Image source)