A Gnome’s Travels for Science
Scientists send a garden gnome around the world to help learn about gravity
The Gnome Experiment shows how the effect of gravity changes at different locations on Earth. (Courtesy: THE GNOME EXPERIMENT / www.gnomeexperiment.com)
From high mountain peaks to laboratories deep underground, a garden gnome named Kern has been trotting the globe to reveal a little-known fact about our planet: The force of gravity is not the same everywhere on Earth. Gravity is the force that pulls objects towards Earth.
A company that sells precision scales is behind Kern’s travels. It sends the gnome and a digital scale to scientists around the world. The experiment shows why the company has to adjust each scale it sells to account for local gravity differences.
Kern, who travels alone via the United Parcel Service Inc. (UPS), is weighed by the scientists at each location. Weight is a product of mass times gravity. This means that in spots where gravity is pulling more, Kern will weigh more, and in places where this force is less, the gnome weighs less.
“Kern has by far weighed the heaviest at the South Pole and lightest at Mexico and Mumbai, India,” says James Nester, creator of the Gnome Experiment.
Earth is not a perfect sphere. It’s actually shaped more like a potato. As Earth spins on its axis, the planet bulges at the equator, an imaginary line around the middle of the planet between the North and South poles. So on the equator, Kern is actually farther away from Earth’s center compared with at the poles, reducing the effect of gravity by 0.2 percent.
Additionally, at the poles, Kern is basically spinning on the spot. But on the equator, the gnome is traveling in a circle around Earth’s center. The spin creates a centrifugal force that slightly pushes Kern away from Earth. Centrifugal force causes an object rotating around a center point to move away from the center. It further reduces the effect of gravity.
Earth is also not perfectly smooth. Mountainous areas have more mass. Therefore, the pull of gravity is greater there than at sea level.
Kern has been weighed at many places of geographic or scientific interest—such as the former home of Sir Isaac Newton, one of the first scientists to study gravity, and CERN, a famous laboratory in Switzerland. For more information, you can follow Kern’s journey on his blog.