[ SKEPTICAL INQUIREE BENJAMIN RADFORD Benjamin Radford is a research fellow at the Committee for Skeptical Inquiry and author or coauthor of nine books, including Bad Clowns.

Egging the Equator

I’ve heard that there are some special science tricks you can accomplish only at the equator, including balancing an on its end. Is that true? Q: —M. Favaro On a recent trip to itational force. The combined effect is Ecua dor, I spent a about 0.5 percent.) He then told us— : week at a jungle lodge incorrectly in my growing suspicion— near the borders of that this effect would be demonstrated A Colombia and Peru. by a simple science experiment involv- The only access is ing an egg. by boat on the Napo River, one of the Once he was satisfied that the stake major tributaries of the Amazon. The was perpendicular to the ground and protected preserve is home to several correctly aligned with the equator, our Indian tribes, and eco-tourism is popu- guide then placed an egg on top of the lar; the days are filled with jungle hikes, nail, and after about two minutes he kayaking, and watching monkeys, birds, stepped back so that we could all ad- and river dolphins. mire his achievement: the egg was in- Among the touristy things to do in deed standing upright atop the nail on Ecuador—a country named for its geo- the stake. It was impressive, and we all graphical location—is visit the equator. took turns photographing this apparent In the dozen or so countries though quirk of physics. which the equator passes, a small but I could not deny that it had been significant commercial industry has monument bearing a metal plaque de- done; I had no reason to suspect trick- emerged associated with it, including claring it “Monumento Mitad Del ery or legerdemain. When our guide equator tours, T-shirts, and hats (an Mundo,” or the monument at the mid- removed the egg and handed it to me impressive feat for an imaginary line). dle of the world. After obligatory tourist to try it for myself, I confirmed that it was indeed a genuine raw egg. (I at- There are several claims about inter- photos were taken, our guide offered esting or unusual natural phenomena tempted to duplicate the feat but gave to show us an amazing sight. From a said to happen only at the equator. up in under a minute, passing the egg backpack at his feet, he produced an Perhaps the most famous is that water to someone else whose patience was re- egg and a wooden stake. The stake was goes down a drain in opposite directions warded with another success, resulting about eighteen inches long and had a above and below the equator due to the in another -related ovation.) Coriolis Effect. Though this nugget of nail hammered partway in at the top. However, there seemed no logical curiosa appears in many trivia books, it He carefully centered the stake about or scientific connection between the is dubious. While it is true that given a two feet in front of the monument and claimed principle and effect: Assum- large enough body of water and a per- drove it into the moist earth. As he did, ing an egg did in fact weigh less at that fectly symmetrical basin and drain spout he announced, correctly, that we weigh particular spot than another only a few the water would empty in different di- slightly less at the equator due to the meters or miles away, it wasn’t clear why rections, as a practical matter the curve centrifugal force of Earth’s rotation. (A that would allow it to stand on its end. of the container has a far greater influ- second effect is that Earth’s slightly flat- The mass of the egg was the same, and ence on which way water drains (Bobick tened shape means a person standing at thus presumably the center of gravity and Balaban 2003, 6). the equator is slightly farther from the over the nail head was the same regard- One day during a jungle hike, my center of the Earth than he would be less of its location. Did that mean that a companions and I paused at a concre