What could be causing my cloud chamber experiment to fail?

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Discussion Overview

The discussion revolves around the challenges faced in conducting a cloud chamber experiment, including the materials used, temperature conditions, and potential reactions occurring during the experiment. Participants explore various factors that could affect the success of the experiment, including the use of different radioactive sources and the presence of water in the alcohol solution.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant describes their cloud chamber setup and expresses curiosity about the reactions involving free electrons and ionization processes occurring with water and alcohol.
  • Another participant questions the inclusion of water in the experiment, suggesting that moisture could hinder the cooling process and recommending the use of denatured ethanol instead.
  • A participant raises a concern about the temperature difference between the experiment's cooling requirement and the temperature of dry ice, questioning its potential impact on the experiment's success.
  • There is a discussion about the cost and safety of using Cobalt 60, with one participant clarifying that small encapsulated sources are typically used in educational settings.
  • A participant shares their experience of using a different radioactive source, Americium, after initially using Cobalt, but reports no success in their experiments.

Areas of Agreement / Disagreement

Participants express differing opinions on the appropriateness of using water in the alcohol solution and the implications of temperature differences. There is no consensus on the best approach to achieve success in the cloud chamber experiment, as multiple competing views and experiences are presented.

Contextual Notes

Participants mention various assumptions regarding the materials and methods used, including the effects of moisture and temperature on the experiment's outcomes. The discussion does not resolve these uncertainties.

Who May Find This Useful

Individuals interested in experimental physics, particularly those conducting cloud chamber experiments or exploring the use of radioactive sources in educational settings.

whitay
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I'm conducting a cloud chamber experiment using:
Jar (black lid)
Felt(black)
Methylated Spirits (96% ethanol)
Water
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 occurring with the free electron(s) floating around? With the naturally occurring 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?
 
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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.

Zz.
 
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?
 
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.
 
Danger said:
The last time that I paid attention, Cobalt 60 was about $10,000 per ounce.

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

http://www.canberra.com/products/822.asp

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!
 
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.
 
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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