How should or why should a polyester sheet make a fluorescent light bulb glow?

06 September 2009

Question

How should or why should a polyester sheet make a fluorescent light bulb glow? I accidentally rubbed my pillowcase, which is 100% polyester against the mini-fluorescent bulb, which is in my bedside lamp. And it glowed for a split second, I repeated this numerous times and every time it worked as long as I touch the contacts. It’s just a simple lamp from Wal-Mart made in China. Am I being exposed to some kind of random chemical or radioactive toxin or something?

Answer

Dave - No, this is perfectly normal. In fact we did a Kitchen Science on this a couple of years back. Basically polyester is a polymer which is quite good at charging up. So if you rub that against your hair or against other sheets it would tend to, as it touches the sheets it would slowly get electrons transfer to it (or away from it, I'm not sure which way with polyester) and so it gained a charge. This means if you move it near a fluorescent tube, a fluorescent tube is basically hollow tube with some very low pressure mercury gas in it. Some of that mercury gas will be ionized, it would've lost electron, you move a charged thing near that some of those ions will move towards or away from the charged thing, will accelerate along, will hit other mercury atoms and knock electrons off those and then you'll get a cascade effect. And get a little bit of electric current flowing through the tube one way, when you take it away then it will flow back again, and that will transfer energy to the mercury atoms some of that they will release as ultraviolet light. This will hit the sort of white coating inside of the tube and that will emit visible light, which you can see as this flash of light. Chris - So there's nothing radioactive about your bed, it's okay then, you're okay.

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