# Coriolis Effect on the equator.

Well, I started my physics class today and this was my homework question: What direction does water flow at the equator? I know that it is counter-clockwise on the northern hemisphere, and clockwise in the southern. Well, what about right on the equator? Would it jsut sink right down? This doesn’t necessarily have to be about water either, what if a plane was shot down right over the equator? Which way would it spiral? Or, wouldn’t it at all? I am actually surprised that this question hasn’t been posted here before, I think it hasn’t at least.

Tell ya what. Go to Cecil’s columns and look this up. Conclusion: this is an urban legend.

Somehow, I don’t think this will satisfy your teacher, though. But technically, at the equator (and under what I imagine are some idealized assumptions), there is no Coriolis force, as you said.

I suppose it would have helped had I posted the link, huh?

http://www.straightdope.com/classics/a1_161.html

You didn’t really post this, did you? First search the archive for something simple like “coriolis.” You might come up with Cecil on Coriolis

As Cecil said in his report, "water drains whichever way it wants to. Never mind where you are located. One can also suggest that a plane which had been shot down might sprial one way or another depending on which wing got shot off.

Think as the Earth being spherical like an orange. You can take an orange and slice it into circles of different radii. You can do the same thing with the Earth. The “centripedal” force of a particle, mass m, going in a circle around a central point (r away at speed v) is given by F=mv*v/r.

If you go around the outside of a sphere, which has a big stake through its centre, the “r” value can be defined with respect to the stake. As you go around the sphere, the “r” changes since you are going through cross-sections with different radii. This causes the Coriolis force, since a change in direction of acceleration prodces a force as these are vectors.

If you stay on the Equator, the radius of the orbit relative to a stake does not change. If the angular acceleration is zero, there is no Coriolis force.

Even at the poles, the Coriolis force is only one factor affecting how water flows, and less important than the shape of the container holding the water, what mpvement it has based on its filling, etc. The clockwise stuff makes nice theory but rarely pans out.

This has been discussed before.

“Orange” you glad Dr-Paprika was here to explain this to you?

I’m glad I didn’t say banana.

Cripes, now how am I gonna get wimmin bent over my bathtub, checking out my mysterious vortex?

Anyone have any etchings they want to part with?

Here’s how to to get that A+ in physics:

“What direction does water flow at the equator?”

A: Downhill.
Unless assisted by a pump.

Hmmm, aeroplanes do not “spiral” after being shot down due to the coriolis effect, they general spiral because:

a. The dead pilot is slumped over the control column

b. One wing has been shot up causing it to generate less lift than the undamaged wing.

C. The aircraft is in a stalled/spinning condition where one wing has a high angle of attack causing it to stall, while the other wings angle of attack is low enough to allow it to generate lift, same effect as in b. above.

One place that we do see the coriolis effect acting all the time is in weather patterns. This causes cyclonic and anticyclonic flow in high and low pressure systems. Around the equater there is very little circular motion in weather patterns (aside from cyclones of course, but they generally occur in the tropics rather than the equator).