Most installations of Foucault’s pendulum have something that nudges the pendulum to keep it swinging. Most? All, probably. Read the small print on the display, it probably explains that.
To someone who is not convinced that the earth is a sphere, that would just be taken as evidence that everybody is just cheating on the pendulum results.
I’m a third of the way through Foucault’s Pendulum, I wish I didn’t have to read it in translation.
I’m with Friedo - if your friend believes the world is flat and that she has reached this conclusion through “logic,” you’re not going to get very far with her using reasoned explanations.
You could try asking her to show you the edge. If the world is flat like a coin, then surely it must have an edge - and you’d think if there were an edge, someone one have fallen over it by now.
Of course, they have, but none of them are talking about it.
Here are some natural phenomena that are dependant on the earth being round:
Tides
Time zones
The fact you can’t see the North Star from the southern hemisphere
Or Sirius from the North Pole
The coriolis effect (as seen in hurricanes)
The gulf stream
The fact that great circle arcs are shorter than straight lines
The waves propagated by earthquakes
In short, the amount of evidence that has to be discarded to maintain belief in a flat earth boggles the mind. I’d say refuse to take her seriously at all until she can attempt to explain how all these work in a flat earth. Since she can’t, ask her if it’s logical that those who have actually looked at the evidence are all wrong.
I just came back to my office after a nice walk. As I looked up into the sky, I noticed a curious thing: A jet contrail stretching from one horizon to another. The most curious aspect of this was: It was curved! Now everyobdy knows that when a jet gets high enough to leave coherent contrail, it is at a steady height of several thousand feet. The plane is traveling in a straight line, yet its trail curves. How curious.
I wonder if Apollo’s chariot follows a similar pattern as it pulls the sun across the sky?
waterj2, I am afraid that would not work. Someone who believes the world is falt is not going to accept the coriolis effect or anything of the sort. Anybody who understands the coriolis effect knows full well the Earth is not flat.
I have my doubts anyone can really believe the world is flat and I think it is probably a joke.
Here’s something I didn’t learn until a few years ago. Most people throughout history did NOT think the Earth was flat.
Christopher Columbus, back in the 1480s and 90s was not trying to convince Queen Isabella that the Earth was round. What he was trying to convince her was that the world was small enough to sail around it without running out of supplies and food during the journey. No one knew about North America and so they said it would be impossible to sail West and reach land before they died.
What does this mean? It means that people in the 15th century knew more about the world than this woman does. My advice? Tell her that you hope whatever sock puppets she prays to have mercy on her soul.
Round-earth deniers are a bit of a hobby of mine. Here are some links for those who are interested:
An article on Charles K. Johnson, president of the Flat Earth Society, who says the Earth is flat, and seems 100% serious.
The Myth of the Flat Earth, a short article on the phenomenon Enderw23 mentioned, the propagation (by the likes of Washington Irving and Bugs Bunny) of the myth that Columbus was the first person to think the Earth was round. Don’t mistakenly tear into this strawman when debating with creationists!
Minor Nitpick. Eratosthenes was a greek living in Egypt during the Hellenic period. After Alexander conquered everything his greek/macedonian generals split up the empire. Egypt was a seperate kingdom, but ruled by the Greek Ptolemy dynasty. This is why I get so annoyed with people who think Cleopatra was black. Leaving aside the fact that the Egyptians weren’t black, Cleopatra wasn’t evan an Eygptian, she was Greek!
Anyway, although the Ancient Egyptians had a lot of rough engineering skills, they didn’t have the systematized mathematical theory that would have let them calculate this.
Everything else was correct…the well was at the tropic of cancer, the sun shone straight down on noon of the summer solstice.
[QUOTE]
*Originally posted by Crafter_Man *
**
Cut ya in half and count the rings, of course!!! (Sheesh!!! 
)
The easiest way to deal with a statment like that is to give them the explanation, and if they are not convinced, leave them to sit in their own ignorance…(Unless of course they keep comeing back at you…then you shoot them out into spance and let them have a look for themsleves… )
Lemur866, Minor nitpick: while I suppose my term ‘ancient Egyptians’ is misleading, the events described were, in fact, in Egypt and did, in fact, occur in ancient times.
Exactly how does your non-sequitur about the nationality of Cleopatra relate to the shape of the earth? No one in this thread mentioned her until you did.
Why do you use the phrase ‘Ancient Egyptians’, with the capitalization of Ancient indicating a proper name? With that capitalization my statement would have been incorrect, but I didn’t use that phrase, you did. That’s two strawmen you attacked during your post…
What about the fact that you can’t send a radio signal, no matter how powerful to someplace on the other side of the world? (Without bouncing it off of a satellite)
Oh really? so those people in Austrailia were lying to us in Quincy, IL in 1993 when they called to say they could hear WGEM 1440 AM radio? The radio kept up at full power even during the night because it coordinated the flood response.
Oh well… I guess I was wrong then. I always thought that was true. 
I guess it’s officially time for me to stop posting.
In addition to RM Mentock’s reply, you could magnetize the ball, and have it attracted by other magnets under the floor, or deflected by an electric field as it swings, have air currents circulating to blow the ball in the right direction, or have the ball not quite spherical, to get deflected just a little each time as it swings. A little weight inside the ball, which moves left and right as the pendulum swings to and fro, could get the little bit of deflection you need.
In thinking about why someone would believe the Earth is flat, it’s not just that they’re nuts, it’s that they are very arrogant. Think about it. They “know” better than everyone else. What a nice, superior feeling it must give them. Arguments won’t sway them, because that would mean admitting they are wrong. If the Earth truly were flat, they’d be the ones saying it was round.
AM radio can bend with the curvature of the earth. FM radio goes in a straight line (in effect) so you lose the signal once you travel far enough away and curve ‘below’ the signal. Theoretically you could get an FM signal on the moon.
I once listened to an AM radio station out of Boise, Idaho in Phoenix, Arizona.
Ahhh… so we were both right. I didn’t know it was just FM that went straight. I guess I’m not an idiot after all.
In 'Nam, my dad (Green Beret radioman) would sometimes swap civilian crystals into the radio and talk to a guy in Dallas (at night, of course).
Actually, he didn’t. I made that up. (wink, wink, nudge, nudge, nat’l security, classified, etc.)
Does she wonder why only the Earth is flat, while everything else in the solar system is spherical?
Does she think gravity merely pulls “down,” rather than toward the center of the Earth?
How thick does she think the earth is? If we dig a hole to the underside, what would we find?
And doesn’t she wonder why people can go around the world in absolutely any direction, and still get back home?
Does she think that when someone travels around the world, that they reach a place that’s just like the place they left, and populated with identical people?
And how does she explain the fact that it’s daylight in some parts of the world, and night in other parts, not to mention the perpetual day/night in the arctic/antarctic?
And how does she explain the seasons, especially how they’re reversed in the southern hemisphere?
And if the Earth is flat, are the arctic and antarctic all stretched out, like on a Mercator map? What would she consider to be a “true” map of the world?
Well all of you, thanks for the help. I do not know this wingnut personally (thank god, I’d go nuts) so I don’t know what her views are on what the world “actually looks like”. The easiest way I think I can give her some gentle prodding is to see if I can get her to acknowledge that the Olympics were being brodcast live (most of the time). If that is the case, it was night here and daytime there. I think she could wrap her mind around that one. Radio waves, tides, et al would be simply shrugged off since she wouldn’t know.
Then again, she will probably think there was a conspiracy with the TV stations now… ugh… like many have said, someone who actually believes this crap will change their mind very easily.