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Re: Unsafe High School Science Project
I would suggest, for openers, concentrating on the electrical safety
question. I seriously doubt that primitive apparatus such as you describe
could SAFELY produce sufficient current to get that kind of x-ray output.
I would insist on a calibrated, properly operating monitoring device that is
available to the science fair judge. Also (and this comes from my own
experience growing up tri-lingual), the teacher should make sure the student
can explain every facet of his or her work in English, to an
English-speaker, before trying to construct the apparatus. This is a safety
question, not a "bilingual education" question. If the student's English
comprehension is so poor that he or she can't undertand safety precautions,
then the project should stop right there. Then the radiological safety
question becomes part of a number of safety questions.
Just a suggestion
Ruth Weiner
ruth_weiner@msn.com
-----Original Message-----
From: William G. Nabor <wgnabor@uci.edu>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Thursday, April 13, 2000 10:49 AM
Subject: Unsafe High School Science Project
>Dear RADSAFER's:
>
> Yesterday I and a fellow member of the Southern California
>Chapter of The Health Physics Society helped judge the Orange
>County, California, Science Fair, an exposition in which students
>aged 11 to 17 display their science projects. The Chapter offers
>an award to the best project involving radiation. In the past some
>of the projects have been truly amazing and ingenious. Others have
>been less so. This year we ran into one that was frightening,
>presenting a clear and imminent safety hazard to the student,
>possibly lethal. We fully intend to communicate with the student's
>teacher and the fair officials expressing our concern. However we
>wish neither to discourage the student or her teacher from further
>participation in science nor to bring up the specter of big, bad
>radiation. Therefore, I would appreciate any advice any RADSAFEer
>would care to give on how best to proceed. Please address your
>comments to WGNABOR@UCI.EDU rather that to the list in general, as
>I don't suppose many RADSAFEers would be interested in such a rare
>occurrence.
>
> The project was a home-made X-ray machine constructed by a 15
>year-old high school student in the following manner: The power
>supply was a 12 volt DC 10 amp commercial automobile battery
>charger, the output from which was connected to a vibrator. No,
>not that kind of vibrator. This one was a voltage booster. The
>negative output lead from the vibrator was connected to the base of
>an ordinary incandescent lightbulb. The positive lead was
>connected to the tip if the glass globe under several layers of
>aluminum foil, uncalibrated eyeball estimate 1mm thick. The
>student _claimed_ that she used a "geiger counter" to measure the
>output from this device and got a 300 to 1000 mR/hr dose rate.
>
> We immediately started asking questions about this geiger
>counter to determine how likely was it that this reading was
>correct. Unfortunately, English was not her native language. We
>could not determine if the responses we got from the student
>indicated her total unfamiliarity with the physics involved or of
>English. She could not describe the counter. The photograph she
>had of the device was out of focus and overexposed so we could not
>tell what kind of device it was except that we had never seen a
>geiger counter of this sort before. It looked somewhat like a
>Ludlum AC powered area monitor, but was certainly no Ludlum
>product. Neither was it an old civil defense survey meter that the
>U.S. government passed out ad libitum after the end of the cold
>war. Some of these could read in the R/hr range.
>
> We attempted to get some indication of the output of the
>vibrator, which was housed in a wooden box with no external
>markings of any sort. She appeared not to understand the term
>amperage at all and continuously confused voltage with wavelength.
>We could, therefore, not determine either the output voltage or the
>amperage of the vibrator and so remain ignorant of these two
>critical parameters.
>
> Our safety concerns are three: First, the electrical safety, of
>which there was none. With the exception of the power cord to the
>commercial battery charger every connection was bare. Alligator
>clips, aluminum foil, bare wires, even the connections to the
>lightbulb and the 120 volt AC mains, all were fully exposed. This
>represents a potentially lethal and fully unacceptable situation
>which we will communicate to the teacher.
>
> The second was a minor fire hazard as the lightbulb was tightly
>taped to an unpainted pine two-by-four.
>
> It is the radiation hazard with which I am asking help from
>RADSAFE. I am requesting your opinions on the following:
> 1) Remembering that the target is thin glass and about 1mm of
>Al, and that the positive lead is connected to the outside of the
>glass globe, how likely do you think it that this device could
>produce X-rays or beta rays?
> 2) If it can produce ionizing radiation, how likely is it that
>it can produce 300 to 1000 mR/hr? We were not about to suggest
>that she turn it on in the exhibition hall so we could take
>measurements!
> 3) How best can we word our communication so as to prevent such
>a project in the future without discouraging others from interest
>in radiation?
>
> Finally, no, we did not give this project an award.
>
> Thank you for your help.
>**********************************************************************
>William G. Nabor
>University of California, Irvine
>EH&S Office
>Irvine, CA, 92697-2725
>WGNABOR@UCI.EDU
>mailto:wgnabor@uci.edu
>**********************************************************************
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