Tomath
Neon
Oh this is evil - StephiB-but fun and he hasn't seen it yet-bubble
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Posts: 83
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Post by Tomath on Sept 29, 2005 15:20:35 GMT
Alternating current switches very quickly from flowing in one direction to flowing in another and back. Direct flows in one direction all the time.
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Post by bubble on Sept 29, 2005 15:21:48 GMT
How can you change the direction of a currrent?
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Tomath
Neon
Oh this is evil - StephiB-but fun and he hasn't seen it yet-bubble
heehee- bubble
Posts: 83
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Post by Tomath on Sept 29, 2005 15:26:42 GMT
Well, the electrons flow from negative to positive so you simply change which ends are positive and negative.
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Post by bubble on Sept 29, 2005 15:27:20 GMT
ooooooooooooooooooooooookkkkkkkkkkkkkkkkkkkk.... I kind of get that.
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Post by lotsahillsv13 on Sept 29, 2005 15:54:45 GMT
We were chucking parachutes off tables to see if weight affected air resistance. I timed.
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Tomath
Neon
Oh this is evil - StephiB-but fun and he hasn't seen it yet-bubble
heehee- bubble
Posts: 83
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Post by Tomath on Sept 29, 2005 15:58:18 GMT
I like seeing how fast I can start and stop the stopwatches. I've got down to about 1/10th of a second sometimes.
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Post by bubble on Sept 29, 2005 16:12:51 GMT
I like seeing how close I can guess to an exact second. My best is 0.99
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Post by midgetmogget on Sept 30, 2005 8:09:44 GMT
We were doing an experiment where we had a long strip of paper and we had to use alternating current to make marks on it. How does that work? Not that I'd try it...
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Post by bubble on Sept 30, 2005 14:41:16 GMT
e haven't done that.
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Tomath
Neon
Oh this is evil - StephiB-but fun and he hasn't seen it yet-bubble
heehee- bubble
Posts: 83
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Post by Tomath on Sept 30, 2005 22:42:30 GMT
How does that work? Not that I'd try it... We were doing about acceleration. The alternating current keeps on changing an electromagnet so that it makes a metal point vibrate really fast (I can't remember what speed it is exactly). A strip of paper was pulled along underneath the point. The strip of paper was attached to a weight which pulled the paper along as it dropped. As the paper was pulled through, the distances between the marks increased.
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Post by midgetmogget on Oct 3, 2005 12:31:32 GMT
Aaaaah.
Also - electrickery - Aaaaaaaaaaaaaaaaaaaaaaaaaagh!
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Post by CRG on Oct 4, 2005 18:56:39 GMT
In the words of a phone in water: frazzle, frazzle, caput.
(Wait, that had no relevance to anything! Sorry.)
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Post by StephiB on Oct 5, 2005 5:08:43 GMT
I've just seen that I am moderator of this board. Yay!
Our class has been watching 'Outbreak' because we're doing the immune system at the moment.
My mum's c.1980 astronomy textbook has a bit about black holes, but I don't trust it too much. The particles that get sucked into a black hole release lots of x-rays and that's how they find them. There's a supermassive (I think that's the right word) black hole at the centre of our galaxy but it's not active at the moment. I could go on all day about this. But I won't.
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Tomath
Neon
Oh this is evil - StephiB-but fun and he hasn't seen it yet-bubble
heehee- bubble
Posts: 83
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Post by Tomath on Oct 5, 2005 15:33:09 GMT
One way to find black holes is if they pass in front of a light source (such as a star). The gravitational pull of the black hole will bend the light so that the position of the star will appear to change.
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Post by StephiB on Oct 7, 2005 3:51:39 GMT
I bow to thy superior knowledge.
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