Equatorial physics filter: Please help explain (or debunk) the following three experiment results conducted on the equator.
(My apologies for the very lengthy question)
On a recent trip to Ecuador and the Galapagos, my wife and I had the good fortune of taking a side trip to the equator line, where they conducted three experiments to "prove" our location. I address each in turn.
First, the Coriolis Effect. Now I'm well aware that this subject has been discussed previously here
, and thoroughly debunked, but that doesn't leave me without some questions. The experiment was demonstrated as follows: A large tub of water was hung directly over the Equator line and drained. There was no noticeable spin whatsoever. The tub was then moved 5 feet north of the line, and the experiment repeated. This time it drained with a sprial in one direction (can't remember which way, to be honest). The tub was then taken 5 feet south of the line, and lo and behold, more spin, presumably in the opposite direction. Now when the tub was north and south the line, our guide threw some small bark chips in the water to demonstrate that the water span. I suspect that when she did so, she subtly span the water in one way or another causing it to spin in a particular direction, because as discussed previously, the Coriolis effect simply isn't significant enough to make such a difference. My question relates to the draining over the Equator itself. No spin at all. That's hard to fake I'd think, and I'm curious if anyone might be able to shed some light on whether it has to do with the tub being over the equator, or because of some other factor.
Experiment 2 was the class balancing an egg on the head of a nail experiment. I didn't and still don't buy into this one, if for nothing more than the fact that there was no control experiment. People were successful balancing the egg on the nail over the equator, but there was no experiment demonstrating that you couldn't do this off of the equator. I think that this experiment is total bunk, but I'm curious if anyone knows any physics behind this, and whether there's even any reason to believe at all that the equator has an effect on egg balancing (alternatively, has anyone ever balanced an egg on the head of a nail off of the equator?).
Experiment 3 is the real baffler and where I really need some help. (Please, fellow mefites, accept these observations as true and accurate. I acknowledge that I'd have a hard time believing them if I hadn't been there myself and experienced it.) This was a strength test. Our guide had a visitor clasp his hands and raise them high up in front of his head while he was standing about 5 feet north of the equator. She then attempted to pull down his arms (after instructing him to resist) and was unable to do so. They then repeated the experiment with him straddling the equator line. This time she was able to pull down his arms with relative ease. They then did another similar experiment. Five feet north of the line, the guide had the visitor form a circle with his thumb and forefinger and she attempted to pull the fingers apart (aftering instructing him to resist). She was unable to do so. Again, this was repeated with him straddling the line and this time she was able to easily pull his fingers apart.
Now I'm not stupid, and would have been totally convinced that the guy was a plant except for the fact that there is simply no way to fake the look on his face. That left only one possible explanation -- the guide was simply not trying as hard north of the line as she did on the line itself. Only one way to test this...I had my wife try to duplicate the experiment with me (everyone else started doing this as well). We walked north of the line and my wife was unable to pull my arms down or separate my fingers. We then went to the line and to my extremey astonishment, my arms just fell and my fingers just separated...offering up no resistence. There were about 10 other people there, and this held true without exception. I was (and remain) STUNNED and I simply cannot explain this. I've even thought that maybe some psychological factor could be involved (after the initial demonstration we expected it to be true, so we made it be true, or some such), but I really don't think so. Instead, I ask my fellow readers....Can anyone explain this mystery?