Traveling Gnome Tests Gravity

If you've ever seen Amélie (or perhaps a Travelocity commercial), you're probably familiar with the traveling gnome prank: steal a garden gnome, send him globe-trotting, mail the photographic proof to the statue's baffled former owner. It's silly, and it definitely gains attention --exactly what Kern Precision Scales was looking for as a campaign to highlight slight gravitational differences around the world.

One Antarctic garden gnome, hold the garden
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If the Earth were perfectly spherical, gravity would remain constant across the board. But it's not, as Kern's odd explanatory video --in which the Earth is briefly portrayed as a potato --can explain to you. Things like altitude, local geology, and latitude all affect local gravitational forces. NASA has satellites that collect information on current gravitational fields, and their interactive maps are pretty neat to look at.

A screenshot from NASA's 'Eyes on the Earth', which allows you to see
current gravitational field changes. 

Gravitational discrepancies are important to scale producers like Kern because they can alter a balance's calibration and complicate very exact measurements. A scientist measuring her sample near the equator might get different results than another measuring the same item in a lab in Antarctica.

So, Kern decided to pack a suitcase with a gnome of the company's namesake and a calibrated balance and mail the kit to scientists all over the place.  It looks to me like every continent has been covered, including Antarctica (the place where Kern weighed the most). To date, Kern has visited quite a few big-name labs; his most recent trip took him to CERN in Switzerland. I suppose this means that I'm jealous of a lawn decoration.

Kern's first weigh-in
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At SNOLAB, the world's deepest underground lab, measurements came out slightly lower than expected. The lab lies about 1.3 miles below the earth's surface, which means less rock beneath the gnome guest-of-honor to pull him down. In fact, the rock now above Kern's head contributes a slight pull in the opposite direction. The slight shifts in gravitational forces make Kern lighter.

The official Kern gnome kit. There's only one --no pressure. 

Of course, the Kern gnome experiment is likely not the most exact way of measuring slight differences in Earth's gravitational fields (NASA's satellites have that covered, I should think). There is only one gnome, so the wear and tear of handling and shipping is always a possible confounding factor. Even though exactitude is kind of the point of this project, in some ways it's also beyond the point, which is to raise public awareness of a basic scientific concept in as clever a way as I can imagine. And the whole thing makes for brilliant advertising campaign for Kern.

It's a fun way to communicate science, I've got to admit. And it appears that you can request a visit from Kern. Tempting...