Bed sheets make a fluorescent light bulb glow?

06 September 2009

BED-LINEN

Pillow, sheets and bed linen

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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 experiment 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, slowly get electrons transferred on to it (or away from it, I'm not sure which way with polyester) and so it gains a charge.

This means if you move it near a fluorescent tube - a fluorescent tube is basically a hollow tube with some very low pressure mercury gas in it - some of that mercury gas will be ionised: it would've lost electron. If you move a charged thing near that, some of those ions will move towards or away from the charged thing, meaning they will accelerate along and hit other mercury atoms and knock electrons off those too. 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, 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!

Comments

If I rub my hand back and forth on the sheets or pillow cases a blue glow will emit. Having warm weather here so I don't thinkk it's from static electricity. I washed the sheets and they still glow. There is no florescent bulb in my bedroom. Just find it odd that the previous comment stated their sheets came from China as well.

I was looking for my phone in my sheets and as I moved against the sheets across the bed the sheets glowed a fluorescent green. Then I washed white socks in with the white sheets and now the socks also glow in the dark when in motion against my skin or when pulled and stretched. There is no light bulb to be charged so where is this glow coming from?????

The socks also contain a man-made fibre (probably) and the friction between the sock material when you move it leads to an accumulation of static charge on the socks. When this charge dissipates (discharges) through the sock material it excites molecules in the sock material; this manifests as flashes of light.

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