...quite entertaining ! ...the public's warped perception of radiation makes for some amusing anecdotes !
Jaro
Microwaved socks and other tales from airwaves
JOE SCHWARCZ, Montreal Gazette
Saturday, March 16, 2002
I look forward to my Friday mornings. That's when I spend an hour and a half conversing with the public on CJAD radio. The idea of course is to provide reliable scientific information, answer questions about current concerns and attempt to clear up some of the mysteries that permeate daily life.
But the show is an education for me as well. For more than 20 years it has allowed me to monitor to pulse of the public and to glimpse into its psyche. I have been pleased by callers who have made unusual scientific observations, elated by those with intriguing questions, and frustrated by the occasional demonstration of scientific illiteracy. I have also come to realize that people are burdened with numerous fears, both rational and irrational. And I have learned not to be surprised. Shocked, maybe. But never surprised.
"How do you wash microwaves out of socks?" one inquisitive caller queried. I didn't quite know what to make of this. Quickly, though, we established that he was not worried about having trodden on some stray microwaves but had heard about a device being marketed to reduce the risks of cell phone use. First of all, we need to understand that there is virtually no scientific evidence to suggest that the use of cell phones is dangerous, other than their use while driving. But that has not stopped the inventive marketers. They've come up with a sock-like device that is placed over the phone to absorb the "harmful microwaves."
Instructions that come along with this gem of an idea apparently instruct the user to launder the sock regularly to "wash out the radiation." Total nonsense, of course. Microwaves are a form of energy, and can indeed be absorbed by materials. After all, that's how microwave ovens work. Moisture absorbs the waves and water molecules get energized. They move around more rapidly and it is this motion we sense as heat.
But microwaves cannot be "stored" in a substance for later release. It seems that this belief is not restricted to scam artists who want to protect us from cell phones. A listener once asked how long one should allow microwaved food to stand after cooking to "allow the microwaves to escape."
Obviously, this person had been reading her microwave cookbook, which gave instructions about letting the food stand before eating. This is common practice needed to complete the cooking process. Contrary to what many think, microwaves do not penetrate deeply into food.
The exterior parts are easily heated but the inside cooks through heat transfer by conduction. That's why the food has to be allowed to stand. It has nothing to do with allowing vagrant microwaves to escape.
Microwaves are not the only form of radiation causing undue concern. A terribly agitated caller was worried because after being X-rayed, she was asked to carry the films to show her physician. She had heard all about exposure to X-rays being dangerous and thought that by carrying the films she was being exposed.
Since Sept. 11, a number of people have asked about wearing clothes that have gone through X-ray scanners at airports. They are concerned that the items might become radioactive and pose a risk to their health. Excessive exposure to X-rays can be risky, but X-rayed items do not store and re-emit radiation.
Unfortunately just a mention of the word "radiation" is often enough to alarm people. A gentleman wanted to know what the safest way was to dispose of a broken compact disc player. I didn't realize what he was getting at until he asked whether a laser was a form of radiation, which of course it is. Radiation is nothing more than the propagation of energy through space. Turn on a lightbulb and you are exposed to radiation. The caller knew that CD players used a laser, and since lasers produced radiation, there had to be some risk. A laser beam in a CD player is just a special type of light beam that poses no danger at all, and, of course, it is only emitted when the device is on. So old CD players can be safely discarded. But old laminated pictures might be a different story.
Another caller asked if it was safe to burn a laminated picture in her fireplace. It turned out that she had been recently divorced and wanted no reminders of her former spouse. Burning his picture seemed appropriate, but she had heard that laminated photos were mounted on particleboard, which was glued together with urea-formaldehyde resin. She was worried that the heat would release formaldehyde, which she had heard was toxic.
Indeed, formaldehyde is a problematic substance but the amount released in this particular combustion process would be too little to worry about. Still, I suggested that if she was worried, she could hang on to the picture until the next hazardous waste collection took place in her municipality. She liked that idea. As she told me, "hazardous waste" was an excellent description of her former mate.
Then there was the listener who wanted to know if lighting a match was a good way to get rid of a natural gas smell in a house. That prompted me to launch into a lecture on a common misunderstanding about gas.
Natural gas, I indicated, is just methane and methane has no smell. So odiferous compounds are added to make sure that gas leaks are readily detected. I explained that soot from a burning match could indeed absorb small amounts of smelly compounds, but, I added somewhat smugly, it was not a good idea to go around striking matches in a house that could be filled with methane. It was then that the caller sheepishly informed me he knew all that, but the natural gas he was talking about was more likely to be found in the bathroom than the kitchen. It was I, not he, who had jumped to the wrong conclusion. Like I said, Friday mornings are interesting.
- Joe Schwarcz is director of McGill University's Office for Chemistry and Society. He can be seen on the Discovery Channel and is heard every Friday on CJAD radio at 10:30 a.m. You can write to him c/o The Gazette, 250 St. Antoine St. W., Montreal H2Y 3R7, or E-mail him at joe.schwarcz@mcgill.ca.
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