Interesting story about the motor. Nature is amazing. I’ve been watching a lot of news reports about alligators suddenly eating ladies down in Florida. A lady shot one trying to get into her house yesterday. Reminds me of “The Birds” movie. I guess we can expect a couple of gator sci-fi movies in a year or so.

One time I hooked up my big hi fi speakers to my amp when I moved into a house in L.A. I got a bad hum over the system. I turned off the amp and I still got some hum over my speakers. I unplugged my amp from my speakers and I still got the hum. My speakers were hooked up to nothing, and I still got a low hum. Sounded like about 60 hz. I had to move the speakers to some other part of the room to get rid of the hum. I never figured it out. Surely just a household AC line in the wall wouldn’t make my speakers hum?

Regarding the coffee, I figure the water must have evaporated, but I never actually saw it evaporate, and I never saw steam come out of the oven vent. It happened to me about three times. I did watch the coffee over-heat one time, and it started boiling so I took it out of the oven. But those three other times, the cup was dry, the oven was dry, and the coffee was just gone. I wonder if it all boiled away very suddenly and then evaporated the residue.

I don’t understand why that “flat earth” story was taught in schools for such a long time.

Certainly sailors knew that the earth was round thousands of years ago. They must have discovered that in order to know to put the look-out cage (the “crowsnest”) up at the top of the tallest mast on the ship, so they could see a little beyond the curvature that they couldn’t see while on deck.

When I was a kid, I was riding on a tug boat in the Mobile River. I was sitting down on the deck, along with some adults, and a couple of guys were standing. We were waiting for another boat to come an meet us. One of the standing guys said he saw a light in the distance. The other standing guy agreed. But none of us who were sitting could see it. The sitting adults swore it was not there but the standing adults swore it was. Well, finally, one of the sitting adults stood up and then he could see it. Then we all stood up and we all could see it. Just that little bit of difference in height made all the difference in the light’s visibility, because of the earth’s curvature. Sailors and others must have figured that out centuries ago. Plus, when they sailed South, along the Coast of Africa, they saw the North Star sink lower along the horizon.

Maybe the “average guy”, the average uneducated farmer, thought the earth was flat, but sailors and Egyptian scientists surely did not.

Sam5,

Ah another electrical mystery. 60Hz is all over everything (well in the US -- in Europe it would be 50Hz) from the power lines (and note I don't mean to encourage the "power lines cause cancer" people or anything, just noting we are "awash" in 60Hz fields from the power system), and it (actually harmonics) make a distinctive hum -- just put your ear to a transformer to hear the signature. One little toy I've been dying to buy, but can't justify the cost is one of Fluke's cool little "Scopemeters", essentially a hand-held digital storage scope. I drool over those all the time, but the $3K+ price tag always stops me. I did however buy a cheaper "wavemeter" ($400) with a bandwidth to about 100KHz, that makes a little LED display graph of a signal waveform. Playing with that, I found 60Hz all over everything, including my own body. Heck, drive two electrodes in the ground some distance apart and you'll see 60Hz between those.

However, there's nowhere near enough power to drive a loudspeaker by itself. With an ampliflier, you'll get it from just about anything unshielded. Just take a line-in patch cord and touch the center pin with your finger. (Turn the volume down, and better kill the high frequency with an equalizer if you have one -- it will make a strong "pop" when you first touch it which will go right to the tweeters). You'll hear that distinctive 60Hz + harmonics hum.

It's possible that hum could've been some acoustic coupling, and not electrical, too. In that particular location, it just happened to be some efficient resonator for some 60Hz sound waves, maybe from a nearby electrical device, like a little transformer or motor, or something.

-Richard

I don’t know. I’ve never seen that happen before or since. There was a low hum in both speakers with no wires of any kind connected to the speakers. I had to move them to get away from the hum. I wondered if there was a transformer inside the wall... maybe a doorbell transformer or something. A doorbell transformer is on all the time.

Bingo -- a little doorbell transformer would be a possible source. Little wall warts could be as well, but now they're going to "switching power supply" circuits even for these cheap things -- and you don't need as much transformer iron as before (basically a tiny little coil being driven at very high frequency by the "switcher") A doorbell transformer shouldn't be inside the wall (that would be a bad code violation, but you'll find anything and everything though) but they're typically mounted in the attic or under the crawlspace, mounted right to a floor joist or rafter. Wood can transmit that hum well under the right conditions. If the speaker was just so to act as an efficient resonator, that could be the cause.

If it ever happens again, put your ear to the wall and floor and see if you if can pick up on a hum.

-Richard

I just found this about hot water in a microwave oven. The first one has a video:

http://www.phys.unsw.edu.au/~jw/superheating.html

http://www.truthorfiction.com/rumors...owavewater.htm

How about this one--Magellan was the first person to circumnavigate the globe.

He never got past the Philippines, kids; he was killed. Some of his crew made it all the way, but because Magellan was in charge of the expedition at the time they left port, he gets the credit for being the one to succeed.

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Gillian

"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

"You can't erase icing."

"I can't believe it doesn't work! I found it on the internet, man!"

You are correct (of course), but in a way the story is correct as well, as Magellan had gone to East Asia (Malacca, the Spice Islands) before he went on his trip round America, so he had been from Malacca to Europe, round South America, and back to the Philippines. Not completely round (point to point), perhaps, but near enough to be correct.

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Knowledge is a curse, but ignorance is worse

Its not flat! . . . Oh.
Good subject. I trust my contribution does not start some thing. . The language is my pet beef. When a house burns down it is raised by fire? i after e except after c, nonsense. This list could get huge. At night the stars come out. If they are out how can I see them? The sun does not go down. We are in Earths shadow. and a shooting star never is one.

The Columbus flat-earth myth got started because Washington Irving wrote it in his 1828 novel, "The Life and Voyages of Christopher Columbus" and it stuck with the non-scientific literary types. His actual problem is that everyone else accepted Eratosthenes's figure for the circumference of the earth of about 40,000km and knew he'd die of starvation before reaching the East, but he was sure it was only about 25,000 km. He was wrong but got lucky there was another continent in the way.

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Sue ikki
mi hatenu yume no
hotsure kana---Choko
(This final scene, I
I will not see to the end.
My dream is fraying.)

Taught in the UK at O level Physics that Foucault's Pendulum is proof-positive for the Earth's rotation. Subsequently corrected for those who go on to do A level Physics that it is not, according to Mach and Einstein!

A lot of the examples in this thread are of a type I 've seen called "Lies to children", ie. simplified versions of the truth which, while not correct, gives enough knowledge to build more correct versions on top of later.

If you realize that the early explanation helped understand the later, or made it possible to learn things in another field, you'd be loss disturbed.

The problem with this way of teaching isn't that the explanations are wrong, any simplification is wrong, or that what people think they know is wrong.
The problem is when people don't realise that they've been taught simplifications and go on to believe that what they where taught was the undiluted truth.

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It would be hard to imagine an uglier building that hadn't won a major architectural award.
Trying to make sense of computers, The Error Log.

Ran across an interesting item last evening. My daughter's 4th grade class is learning about myths and tall tales. They have to read at least 4 versions of a tall tale and identify and compare exagerations. Her choice was Stormalong, a tall tale of a giant of a man from the end of the tall ships era. (He is told to be 6 fathoms tall - though I thought fathoms were reserved for measuring depth).

Anyway, one of the versions, in what is obviously a tacked on afterthought at the very end of the story; states that we may very well return to sail power as the primary means of traveling the oceans after our fossil fuels run out.

I found it ironic, and was tempted to instruct her to include that in her list of exxagerations. But alas, the teacher already finds her trying; and I think they've now figured out I have taken a just-smile-and-wave attitude towards their criticisms of her.

BTW - I love the Gangster Penguins in Madagascar, "Just smile and wave boys, just smile and wave."

__________________
Don of Borg - Cool, Calm, Collective.

"Within the next generation I believe that the world's leaders will discover that infant conditioning and narco-hypnosis are more efficient, as instruments of government, than clubs and prisons, and that the lust for power can be just as completely satisfied by suggesting people into loving their servitude as by flogging them and kicking them into obedience." -- Aldous Huxley

Well, no - it's "razed" by fire. Homonym.

But I suspect you knew that...?

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SeanF

"Ask to understand, but don't challenge unless you have the knowledge."--NEOWatcher

The contents of this post are ©2009 by SeanF and may not be copied or retransmitted in any form without the express written consent of SeanF

Really?! I thought the worries about the habitability of the antipodes had dwindled out in the early Middle Ages, more or less.

Sorry to disappoint you. Yes, they did.

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"All your bias are belong to us." Ara Pacis
"A witty saying proves nothing." Voltaire

Your link disagrees, Disinfo Agent:PS: Wait, who are we talking about?

The link shows examples of flat earth thinking in ancient times (but we still have flat earthers now) and round earthers.

Wait a minute... I thought you couldn't add homonyms in a post. Isn't it against Board rules?

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Never attribute to malice what can be adequately explained by ignorance or stupidity.
Isaac Asimov

ADD?

["razz" - am I guilty, too? ]

If the entire house "goes up in smoke", would that allow "raised by fire"?

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.