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Cloud Chamber Experiment

  1. Oct 18, 2006 #1
    I'm conducting a cloud chamber experiment using:
    Jar (black lid)
    Methylated Spirits (96% ethanol)
    Cobalt 60
    Dry Ice

    Concentration about 50-50 with the spirits and water then soaked the felt. Using a projector which produces heat to main a temperature gradient. So far in the 2 runs I've done it has been unsuccessful in producing a cloud, however it is visible that there is rain and the diluted alcohol is being evapourated. One run was straight spirits solution and one was diluted. When I took the lid off the jar after, which was immediately after ceasing the experiment, mist bellowed out and the jar lid had like a liquidy/water feel it to.

    I'm going to try it again tomorrow in the hope of success and with Americium as it's a alpha emitter so ionisation should be far more effective.

    If, from my brief description of how I'm conducting this experiment, you find something errornous tell me. However my question is I'm curious as to the reactions that would be occuring with the free electron(s) floating around? With the naturally occuring equilibrium of H20 -> H+ + OH-, would the electron be attracted to the H+ ions causing H++? Also what would the ionisation be doing to the alcohol?
  2. jcsd
  3. Oct 18, 2006 #2


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    Staff Emeritus
    Science Advisor
    Education Advisor

    Does our recipe actually calls for water?

    Usually, when you are using dry ice to cool it into a saturated condition, you don't want any kind of moisture. That's why it is always recommended that you use denatured ethenol - it has less water. If you do have too much water, it will freeze instead.

  4. Oct 21, 2006 #3
    Dry ice is approximately -78.5 degrees C, Langsdorf experiment says the experiment should be conduct with cooling to -40 degrees C. Does this -38.5 degree difference have great effect?
  5. Oct 21, 2006 #4


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    What on Earth level are you doing this at? The last time that I paid attention, Cobalt 60 was about $10,000 per ounce. I can't help with your question, but that ingredient really caught my attention.
  6. Oct 21, 2006 #5


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    Staff: Mentor

    He's probably using small encapsulated sources at the microcurie level, such as these:


    Sources such as these are commonly used in undergraduate laboratories. They're not very expensive, and they don't require elaborate safety precautions.

    An ounce of cobalt-60 would definltely require elaborate safety precautions!
  7. Oct 21, 2006 #6


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    Well then, I think that I feel a new hobby coming on... :biggrin:

    Nice link, JT. I don't have time to check it out completely, but I added it to my 'favourites' list.
  8. Oct 21, 2006 #7
    Yeah my teacher said it was cobalt but it wasnt, turned out ot be strontium. I've ripped apart a smoke alarm and using the americium now. However no success.
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