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

What moves a lit candle?

  1. Oct 31, 2011 #1
    "Bring a lit candle near the collector after the Van de Graaff Generator is turned on. The flame will deflect away from the collector. This shows the flow of ions away from the collector. If you bring the flame very close, a portion of the flame will be attracted toward the collector. The ions in the flame are separating by charge."

    Does anyone have any suggestions on why this lit candle deflect away from collector and attracted toward the collector? I get no clue.
    Thanks in advance for any suggestions
     
  2. jcsd
  3. Oct 31, 2011 #2

    Low-Q

    User Avatar
    Gold Member

    My 5 cents:
    The carbon in the flame is diamagnetic. Approaching a neodym magnet close to a candle light, will deflect the flame too, but it will not attract to the magnet if it get close enough.

    The ions have a positive charge, and charge the carbon (possibly) with the same charge, and therefor it deflects away. If the flame is close enough it might be attracted to the negative charge very close to the collector(?). I mean if ions is flowing out from the generator, there should be equal opposite charge from where ions came from (??).

    I have an "ionizer" that is used to reduce dust in the air. I will try this experiment when I get home :smile:

    Vidar
     
  4. Oct 31, 2011 #3
    I would like to know more about the property of the frame, which carbon in the flame is diamagnetic. Is there any positive or negative charges on flame? is frame neutral in charges? What process is going on within the frame? C + O2 = CO2 I guess, any free electrons?
    Does anyone have any suggestions?
    Thanks you very much for any suggestions
     
  5. Oct 31, 2011 #4

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    There must be two different effects at work here.

    I think that, when the flame is close, the particles (bits of carbon and other molecules etc.) become polarised and this works in the same way that dust and pieces of paper are attracted to a charged comb: one polarity of charge is nearer than the other polarity - producing attraction. I think it's called inductive attraction and it's why dust doesn't need to actually carry a charge to be attracted.

    When the flame is further away, this electrostatic attraction is much less and the flow of ions away from the generator will 'blow' the flame away.
     
  6. Oct 31, 2011 #5
    Does it mean that the mass of positive ions from collector physically hit and move the Carbon within flame? so it makes ion blowing the flame away. I don't know whether this is any charges on burning carbon or not. Before carbon becomes CO2, does burning Carbon carry any charges at all?
    Does anyone have any suggestions?
    Thanks everyone very much for any suggestions
     
  7. Oct 31, 2011 #6

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    Why would there have to be a charge on the carbon? When C and O atoms combine, a covalent bond forms (no?). Why introduce ionisation? However, polarisation is a much more likely effect. Imho.
     
  8. Nov 1, 2011 #7

    NascentOxygen

    User Avatar

    Staff: Mentor

    This. http://www.plasma-universe.com/Flame" [Broken]
     
    Last edited by a moderator: May 5, 2017
  9. Nov 1, 2011 #8
    Referring to your link, candle flame is a plasma, which carry positive ions.

    When you bring the flame very close, a portion of the flame will be attracted toward the collector. The ions in the flame are separating by charge.Is polarisation is a much more likely effect?

    Does anyone have any suggestions how to explain what is going on during polarisation?

    Furthermore, will the flame release positive ions into air through smoke? since the candle is neutral iniitially, where does negative ions go in this situation?

    Thanks everyone very much for any suggestions
     
    Last edited by a moderator: May 5, 2017
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: What moves a lit candle?
Loading...