Equator Archives - Eva Varga

November 21, 20144

On our last day in Quito, we had a few hours of leisure time prior to our flight to Guayaquil. Just enough time to visit La Mitad del Mundo, the place where Charles-Marie de La Condamine made the measurements in 1736 showing that this was indeed the equatorial line. His expedition’s measurements gave rise to the metric system and proved that the world is not perfectly round, but that it bulges at the equator.


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Despite the touristy nature of the equator monument that now sits here (souvenir shops and small restaurants crowd the entrance), there is simply no excuse to come this far and not see it. You just have to get into the spirit of things. It was worthwhile to visit for the family picture straddling the “equator” with the monument in the background.

The highlight of this excursion, however, was the Intiñan Museum just a short distance away – where the proprietors proudly advertise it as the home of the “true” equator. The museum is bisected by a line of red paint. GPS tests come back with mixed results, and the rocky surroundings make accurate readings difficult to obtain, but we were close. Very close.

Our visit here was much more rewarding in regards to having a true equatorial experience.  Located in the foothills of the Andes Mountains, the Intiñan Museum features an unexpected triumvirate of physics, folklore, and culture.

A museum guide conducted an informative tour around the premises, stopping occasionally at life-size dioramas depicting Ecuadorian daily life. The central focus of the museum is a totem pole surrounded by several stations, each designed to test the unique physical forces at work in the equatorial region.


Science Experiments at the Equator

Some of the science experiments at the Equator are clearly parlor tricks, but others are appreciable demonstrations of physics. The one demonstration that was the most impressive (if you use the audience’s exclamations of surprise as any indication), was how water drains at the equator compared to the northern and southern hemispheres.

I recorded a video while we there with the intentions of sharing it with you – but as I was fact checking for this post, I stumbled upon this video that was better than mine. I made the mistake of stopping each time the guide moved; I didn’t record the entire process. I thereby missed the ruse.

Admittedly, I was as caught up in the parlor trick as everyone else. This was contrary to what I had been taught in physics class. I knew this was a misconception I had to address with my kids upon our return home.

His trick plays on the idea that people think water will drain (or flush in a toilet) in one direction north of the equator, and in the opposite direction in the southern hemisphere. Most people know hurricanes rotate one way (counterclockwise) in the north and the other (clockwise) in the south, so there’s some basis for this. This fact is due to the Coriolis effect.

Using our North Star Geography program as our guide, I began a discussion with the kids about the Coriolis effect.

 “Named after nineteenth-century French mathematician and engineer Gustave-Gaspard Coriolis, the Coriolis effect is the force the rotation of the earth exerts on air, water, and flying objects.”

This only works over distances where the spin of the Earth makes a difference when you head north or south. Your bathtub or the basin in the video is simply not big enough to make a difference. Random currents in the water completely overwhelm any tiny coriolis effect going on.

As a Brand Ambassador for Bright Ideas Press we have received a complimentary copy of North Star Geography in exchange for our honest insights about how this program is working in real life with our family.

Let’s review the video very carefully; here’s a play by play:

  • First he goes through a show of finding north and locating the position of the Equator.
  • He then goes to a water filed basin on the Equator. The basin is already filled – just as it had been when we were there. The point is, the water had been sitting in the basin for awhile. When he pulls out the plug the water drains straight down.
  • He then grabs the basin and bucket and moves a few meters south. He pours the water from a bucket, making sure the water is flowing in to the left of the drain hole. When he does this, it sets up a natural clockwise spin to the water overall. Low and behold, when he pulls out the plug, the water drains in a clockwise direction.
  • He then moves moves the basin to the north of the Equator. Someone steps in front of the camera so it is a little hard to tell, but you do very certainly see him pouring the water to the right of the drain hole, natural counter-clockwise spin to the water overall. No surprise then when he pulls out the plug, the water drains in a counter-clockwise direction.

It has nothing to do with where the basin is; if he had poured the water to the right of the drain in the north, it would have drained in a counter-clockwise direction and vice versa. As for the water in the basin on the Equator – as you recall it had been sitting there for a while – he probably filled it carefully so there was no circular motion of the water. That way, when it drains, it drains straight down.

But the bottom line is this – for hurricanes and launching missiles, yeah, the Coriolis effect is important. For draining sinks and flushing toilets, though, it’s all a matter of spin.

Try it Yourself !

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