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Physics/ionizing air measurements

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Question
hello,
would an electroscope be useful in detecting air ionization from a negative ion ionizer? if i put it near the output of the ionizer would some of the negative ions transfer their charge to the rod and leaves. i just am not sure if there is a reason for the ions to do so as the electroscope terminal is not grounded and as soon as a few impart a charge the rest will be repelled away. maybe i could use a metal tube connected to the electroscope terminal and blow the ionized air through the tube using the feraday ice pale effect to build up charge?
thank you,
gene

Answer
Hello gene,

I have found many web sites that discuss the use of an electroscope to detect positively ionized air. I will list some below. The electroscope is initially given a negative charge. The electroscope indicates the presence of positively ionized air by discharging much faster than it otherwise would. The positively ionized air discharges the electroscope by accepting electrons.

I can't think of any reason that negatively ionized air would not donate electrons to a positively charged electroscope. However, I have not confirmed it. (The 3rd link in the list below takes you to a site that does vaguely indicate that it could work both ways.)

The web sites that I found:
http://books.google.com/books?id=-sE7JVywygQC&pg=PA192&lpg=PA192&dq=electroscope
http://books.google.com/books?id=D8DzBJWvRDcC&pg=PA150&lpg=PA150&dq=electroscope
https://www.nde-ed.org/EducationResources/HighSchool/Radiography/electroscope_popup.htm
http://science.howstuffworks.com/electroscope-info.htm
http://www.darvill.clara.net/nucrad/detect.htm#goldleaf
http://www.iaea.org/Publications/Magazines/Bulletin/Bull234/23405043136.pdf

I hope this helps,
Steve

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Steve Johnson

Expertise

I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

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I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

Education/Credentials
BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University

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