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Electricity and Magnetisim — Parallax Forums

Electricity and Magnetisim

Beau SchwabeBeau Schwabe Posts: 6,568
edited 2013-01-13 12:34 in General Discussion
I gave a science demonstration to my oldest daughters class today during my lunch covering some of the history of Electricity and Magnetism mainly focusing on magnetism.

Covered magnetic poles ... Opposites attract, and Likes repel, but I threw everyone off when I asked based on attraction and repulsion, why would a magnet want to stick to a refrigerator ( a neutral ) :-) ... showed what an electrical magnet does, progressing to a functioning telegraph, an then concept building toward making a functioning speaker in the classroom and how the same device could become a microphone. Transcending that into a motor and showing a working motor, and how it could be used in reverse similar to a microphone. I had a hand cranked 'generator" which essentially was a motor in reverse. Attaching two motors together one operating as a generator while the other operating as ... well.. a motor, ...and how changing the load on the motor increases the resistance or amount of work required by the generator.... To wrap things up, we finished with a penny and magnet race down an aluminum tube as to which one would win the race. Based on some of the concepts that we went over, they were to form a hypothesis as to why the magnet would always come in last place.

I just have to contemplate though how electromagnetism was essentially accidentally discovered by Hans Christian

Comments

  • Mark_TMark_T Posts: 1,981
    edited 2013-01-10 16:16
    A nice little demo with an old broken speaker I like: cut out the cone and remove the cone from the coil and attach to long thin wires. Place in the magnet
    assembly and discharge an electrolytic cap into the coil so it jumps out of the magnet!
  • ElectricAyeElectricAye Posts: 4,561
    edited 2013-01-10 16:46
    ...Transcending that into a motor and showing a working motor....

    I'm guessing
  • lanternfishlanternfish Posts: 366
    edited 2013-01-11 01:02
    If I recall correctly (from some obscure memory of a lecture many years ago)
  • Tracy AllenTracy Allen Posts: 6,664
    edited 2013-01-11 08:52
    Beau -- that sounds like a long lunch hour! It's good that Parallax appreciates that kind of giving back.

    There is Hermann von Helmholz too, born the year after the discovery of the electromagnetic phenomenon by
  • lardomlardom Posts: 1,659
    edited 2013-01-11 09:14
    @Beau Schwabe, your daughter has to be proud.
  • ercoerco Posts: 20,259
    edited 2013-01-11 10:37
    An excellent question about Hans Christian
  • Heater.Heater. Posts: 21,230
    edited 2013-01-11 11:33
    That
  • ElectricAyeElectricAye Posts: 4,561
    edited 2013-01-11 12:20
    Heater. wrote: »
    That
  • Heater.Heater. Posts: 21,230
    edited 2013-01-11 13:17
    Electric Aye,
    You'd be dead now.
    A small price to pay.
  • ElectricAyeElectricAye Posts: 4,561
    edited 2013-01-11 13:26
    Heater. wrote: »
    Electric Aye,

    A small price to pay.

    Gosh, Heater, if you're that desperate to witness genius in action, you're welcome to watch me give a lecture on the Eastern Skunk Cabbage. Who knows? Maybe I'll have an epiphany about its metabolic biochemistry right before your very eyes. And you won't even have to die to see it. Much.

    http://forums.parallax.com/showthread.php/145277-Science-Fair?p=1156995&viewfull=1#post1156995
  • Heater.Heater. Posts: 21,230
    edited 2013-01-11 15:55
    I'd love it.

    As long as that thing doesn't start shouting "Feed me Seymore"...
  • Mark_TMark_T Posts: 1,981
    edited 2013-01-11 16:01
    Heater. wrote: »

    How many times have people been at a lecture where something so earth shattering was actually discovered in real time in front of their faces? Who were the audience, did they comprehend what had just happened?

    No, but I was at a lecture where a motorbike was driven up and down the steps of the lecture theatre... (not by me I hasten to add).

    The
  • kwinnkwinn Posts: 8,697
    edited 2013-01-11 22:47
    Heater. wrote: »
    Electric Aye,

    A small price to pay.

    Not really. Picture all the advances in science and technology you would have missed.
  • Mark_TMark_T Posts: 1,981
    edited 2013-01-12 15:30
    kwinn wrote: »
    Not really. Picture all the advances in science and technology you would have missed.

    Well not an issue if a time machine is involved. Of course we know they don't exist or we'd have seen all the time tourists coming back to
    witness the moon landings!
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2013-01-13 08:09
    I just have to contemplate though how electromagnetism was essentially accidentally discovered by Hans Christian
  • Heater.Heater. Posts: 21,230
    edited 2013-01-13 08:14
    Even better:)

    What would we do with out Murphy? Nothing would get discovered.
  • ElectricAyeElectricAye Posts: 4,561
    edited 2013-01-13 08:30
    PJ Allen wrote: »
    ...He was to show that an electric current passing down a wire would not affect a nearby compass needle - when, to his chagrin, it did.....

    You see it all the time, teachers who don't properly prepare for their classes. Serves him right. Perhaps that is why, today, we measure lack-of-class-preparation in
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2013-01-13 12:34
    You see it all the time, teachers who don't properly prepare for their classes.

    Yeah... I think I catch your drift -

    1264430322987.JPEG
    427 x 240 - 23K
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