Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What produce the earth magnetic fields ?

  1. Apr 27, 2006 #1
    I am wonder what produce the earth's magnetic field .Can anyone tell me . Besides , I am doing a experiment to measure the horizontal component of earth's magnetic field . I am using a copper (about 16 mm in length) and a power supply of two volt . I use the copper to create the solonoid but suprisingly the ammeter show that there is no current flow in the circuit . That means that the copper cannot conduct electricity . How it can be the copper cannot conduct eletricity since the wire is made of copper .
     
  2. jcsd
  3. Apr 27, 2006 #2
    The earth's magnetic field is caused by electric curents in the earth's core region. This core is metallic in nature.

    Check this out


    marlon
     
  4. Apr 27, 2006 #3

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The current state of understanding of this matter is very poor. The dynamo effect is the best guess, but still does not answer many questions (like the cause of the pole flips).

    As for your field measurement circuit...we can not tell you what is wrong unless you show a diagram/schematic of the circuit (in the advanced post page, there is an option to attach files) or give us a complete description.

    What principle are you using to measure the field ?
     
  5. Apr 28, 2006 #4

    vanesch

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Naive question of course, but your solenoid is moving/rotating, right ?
    If it is static of course you won't see anything...
     
  6. Apr 28, 2006 #5
    I use the battery to connect to the solenoid so that it become a magnet ,not se the solenoid to generate electricity . But there is no current flow .I waonder why
     
  7. Apr 28, 2006 #6

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    I thought you said that you used a ".....power supply of two volt ..."?

    As Gokul said, without a complete description, who knows what is going on.

    Zz.
     
  8. Apr 28, 2006 #7

    vanesch

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    In other words, you shorted the battery, and now it is empty ? :blushing:
     
  9. Apr 28, 2006 #8

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Sounds like it.

    peter : But that's only a guess. Unless you describe the circuit, no one will really know what happened.

    Use a voltmeter and check that your battery is still okay. Next time, use a series resistor of at least 20 ohms (for a 0.25W resistor). If you don't do this, you will draw a very large current from the battery. Most household batteries are not rated to deliver more than 1A.

    In any case, by making an electromagnet, how do you achieve the objective of measuring the horizontal component of the Earth's field ? Tell us the principle you are using to perform this measurement. Then tell use how you are building a device that uses this principle.

    Of course, if you feel lost, ask for help.
     
  10. Apr 30, 2006 #9
    wat i remember about earth sciences back in high school is that the earth's mantle or core is made up of molten iron and other magnetic material and becoz they are rotating around inside the earth, they generate a magnetic field

    correct me if im wrong...
     
  11. Apr 30, 2006 #10

    Mk

    User Avatar

    I think it is the other way around, the magnetic field is making the core spin.
     
  12. Apr 30, 2006 #11
    I just happen to have a copy of the Scientific American to hand, just as well because this isn't my field at all! "Probing the Geodynamo". It would appear that the mantle revolves faster than the inner and outer core. The upwelling of hot buoyant parcels of liquid iron towards the mantle combined with the Coriolis effect give a rotational speed differential between the core and the mantle and hence the dynamo effect.
    Regards
    Paul D
     
  13. Apr 30, 2006 #12

    Danger

    User Avatar
    Gold Member

    Thanks for that, Paul. Weird... I buy every issue of SA, and I don't remember seeing that.
    Ngk (no way am I going to type out your whole damn name); this might seem idiotically simplistic, but are you sure that there's no break in the continuity of your circuit? Could there perhaps be a defect in the connection into your VOM? That's happened to me a couple of times. If a meter gets beaten around a bit, the plug-ins sometimes don't conduct properly. I learned that the hard way after carrying mine around in the same tool pouch with a few sets of Vise-Grips and a dozen screwdrivers.
     
  14. May 9, 2006 #13
    That is really on my mind too.
    It seems like the most easy suspect is different rotation speeds, since that is what you find on the sun.
    But as far as I can see, many, not all planets, and some moons, have magnetic fields.
    http://gsc.nrcan.gc.ca/geomag/index_e.php

    Still, layman to layman, it seems like you really have to have a magnet present to get the magnetic field from the rotation of the ores.
     
  15. May 9, 2006 #14

    Mk

    User Avatar

    That's why the magnetic field is making the core turn, and not the other way around. Am I right?
     
  16. May 10, 2006 #15
    "The theory of the process is very mathematical and intricate, because to produce the currents, you need not only a flow of liquid iron, you also need a magnetic field, and this field is none other, but the one created by the currents themselves!"
    http://www.phy6.org/earthmag/NSTA1C.htm

    Also, I think there are some problems with the aging of a magnetic field. Hope you got your experiment going again.
     
  17. May 10, 2006 #16

    LURCH

    User Avatar
    Science Advisor

    Considered by many to be the leader in the field;
    http://complex.umd.edu/
    Still no diffinitive answer, but they are producing real datya in a laboratory model.
     
  18. May 11, 2006 #17
    Oh my gosh! It's a good thing they can do this experiment with those tubes and copper and sodium and refrigerator size magnets! That is better than crashing all those LARGE computers on the complexity of the problem! After all, this is taxpayer funded, via the NSF $6billion per year.
     
  19. May 11, 2006 #18

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    All you need to generate a magnetic field is a flow of current. Relative motion of the various depths will represent charge in relative motion, this is a current. Thus a electro-magnetic field will be generated.

    Mk,
    For the magnetic field to drive the core you must have a source of energy. The core is quite massive it would take tremendous forces to drive this mass of metal. What is your source of energy to do this?
     
  20. May 11, 2006 #19
    Relative motion differentiation, in itself, causes electron current flow? Since when?

    Show me an experiment that molten metal, spun at "layerd" differential speeds(such as in a blender-type apparatus) has produced a magnetic field.
     
    Last edited: May 11, 2006
  21. May 11, 2006 #20

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That sounds like a challening experiment on any scale, and I doubt that it has been done on a large scale. It is concievable that small scale would give different results from large scale as it could be a matter of measurability.

    (Perhaps I need to spend some time looking at the above links.)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: What produce the earth magnetic fields ?
  1. Earth's magnetic field (Replies: 5)

Loading...