Notices
Results 1 to 10 of 10

Thread: Triboelectric effect and measuring charge

  1. #1 Triboelectric effect and measuring charge 
    New Member
    Join Date
    Aug 2007
    Posts
    1
    Hi

    Im a student who is doing a project which in part requires the use of the triboelectric effect to charge up dust and then look at the effects of this dust when it comes into contact with a low frequency antenna.

    I didnt study this at school so all I have to go by is the wikipedia page on the subject, my tutor want to measure the polarity and the amount of charge on a rubber balloon when it is rubbed against various materials (eg wool and polyester.) Does anyone here know how to measure the polarity and/or strength of charge on a triboelectrically charged balloon?

    Also Iv assumed that simply putting the dust or sand into contact with the charged balloon will in turn charge the sand, is this correct?


    Thanks in advance for the help!


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Bachelors Degree
    Join Date
    May 2007
    Location
    NC USA
    Posts
    488
    You can determine the polarity of the charge by separately rubbing fur with rubber (or any other combination) to place a positive charge on one substance and negative on the other. See the Wiki page at http://en.wikipedia.org/wiki/Triboelectric_effect. Then see how your balloon behaves as each item approaches.

    To measure the amount of charge, I recall a college lab project in which we used some instrument called a ballistics galvanometer. I doubt if you can find one, but check with your tutor. Maybe he is hoping you would ask. See the Wiki article at *http://en.wikipedia.org/wiki/Electric_charge.


    Reply With Quote  
     

  4. #3 Charge 
    Forum Sophomore
    Join Date
    Jul 2007
    Location
    South Africa
    Posts
    196


    The charged baloon creates a static electric field. This affects a capacitor held close by it by a tiny amount. The capacitor will behave slightly different than usually.
    It also matters what isn't there - Tao Te Ching interpreted.
    Reply With Quote  
     

  5. #4  
    Forum Bachelors Degree
    Join Date
    May 2007
    Location
    NC USA
    Posts
    488
    What instrument would one use to measure the changes in the capacitor?

    That is, can this experiment be performed by the amateur?
    Reply With Quote  
     

  6. #5 Charge measuring 
    Forum Sophomore
    Join Date
    Jul 2007
    Location
    South Africa
    Posts
    196
    :P

    You can use a static electric voltmeter as an alternative.

    The effect on the capacitor may be too tiny to measure. It would require an alternating current source and voltmeter, together with some mathematics, not so complicated.
    It also matters what isn't there - Tao Te Ching interpreted.
    Reply With Quote  
     

  7. #6  
    Forum Bachelors Degree
    Join Date
    May 2007
    Location
    NC USA
    Posts
    488
    *Then why not use the static electric voltmeter directly on the balloon?
    Reply With Quote  
     

  8. #7  
    Forum Sophomore
    Join Date
    Jul 2007
    Location
    South Africa
    Posts
    196
    :-D

    You can try the voltmeter.

    There is another device that allows you to detect a charge, (not measure it). I forgot the name but it is a metal box with electrode on top and a glass side with a rod inside and a gold leaf attached to it.
    It also matters what isn't there - Tao Te Ching interpreted.
    Reply With Quote  
     

  9. #8  
    Forum Junior
    Join Date
    Jun 2007
    Posts
    233
    Quote Originally Posted by talanum1
    :-D

    You can try the voltmeter.

    There is another device that allows you to detect a charge, (not measure it). I forgot the name but it is a metal box with electrode on top and a glass side with a rod inside and a gold leaf attached to it.
    That's basically a Leyden Jar. And it actually will measure the amount of charge to a degree by the distance of the separation of the leaves. The greater the separation (wider the angle) the greater the charge.
    Reply With Quote  
     

  10. #9  
    Forum Bachelors Degree
    Join Date
    May 2007
    Location
    NC USA
    Posts
    488
    *
    No, a Leyden jar is merely a primitive capacitor.

    The instrument with the gold leaves is called an electroscope.

    But there are simpler and more effective devices to detect and measure charge.

    Try this page: http://amasci.com/emotor/chargdet.html.

    (Edit) Oops, I meant this page:
    http://amasci.com/emotor/voltmeas.html.
    *
    *
    Reply With Quote  
     

  11. #10  
    Forum Junior
    Join Date
    Jun 2007
    Posts
    233
    Quote Originally Posted by SteveF
    *
    No, a Leyden jar is merely a primitive capacitor.

    The instrument with the gold leaves is called an electroscope.

    But there are simpler and more effective devices to detect and measure charge.

    Try this page: http://amasci.com/emotor/chargdet.html.

    (Edit) Oops, I meant this page:
    http://amasci.com/emotor/voltmeas.html.
    *
    *
    Sorry, you're correct. It's been a VERY long time since I dealt with any of those very primitive devices.
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •