h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Static Electric Discharges and how to prevent them - A3796301
Author: Galaxy Babe - U128652

This is a 2nd submission - the first time peeps wanted the science explained.

http://www.town.grandbay-westfield.nb.ca/fire/000000gas.html

There has been a bit of publicity in recent years about car fires caused by static electricity while refueling. Now that most people pump their own gas, and also the insulation and grounding properties of gas tanks have changed by the addition of plastics, many more women than men cause fires while refueling. The theory is that they are more prone to re-enter their vehicles during cold eather, build up a static charge and cause a dangerous explosion and fire when touching the filler again...thought you might consider this as an interesting and useful discussion .

A great idea for an Entry.

I have a few suggestions; I will formulate them more coherently when I'm sober tomorrow.

B

Thank you Formerly Phred!
I've completely reworked that section. It was well worth adding that information!

*waits for Master B to sober up*

There's an Entry on the Lisitania (currently 'Recommended')A4803284, to which you could link

Lusitania A4803284

Thanks!

Hi Gb,

A fascinating subject. It looks on first view very good,

I would suggest a small change to the Lusitania section. It was not a hospital ship. It was a huge ocean liner. There has never been a definitive answer for the huge explosion that ultimately sank the ship: I would just say that a probable cause may have been a dust explosion caused by static electricity in the coal bunkers. It is known that aerosolised coal dust can explode violently when a discharge of electricity is sent through it.

I'm a bit busy at the moment but I'll try and get around to looking at your article later.

Woodpigeon

'It was not a hospital ship. It was a huge ocean liner'

That was my fault. At the time I sent GB the info, it had been my recollection that she was being used as a hospital ship (a la Canberra during the Falklands War).

.

Thanks Woodpigeon

Does this sound better?

"The ocean liner Lusitania exploded when it was torpedoed off the coast of Ireland in 1915. The force of the explosion startled even the German U-boat commander, and there was speculation that the ship had been carrying explosives. The torpedo probably penetrated the hold (which was empty except for coal dust, as the ship had just crossed the Atlantic), creating a dust explosion caused by static electricity in the coal bunkers. It is known that aerosolised coal dust can explode violently when a discharge of electricity is sent through it."

Sorry radioactiveBigAl1, didn't see you there as I was updating.

No problem, about the hospital ship...I'm always a bit confused, do you call an ocean liner a ship or a boat?

I'd go with ship, GB.

Wow, it's changed quite a bit! The science bit is a rather succinct and clear explanation. You still need to mention tribocharging though, which is the correct term for charging things by rubbing them together.

The mobile phone and refuelling stuff is confusing. A lot of the "controversy" has been about the possibility of electric currents, induced in or around the fuel tank by the phone's radiation, causing a spark. This has nothing whatsoever to do with static electricity. If it were merely about the possibility of a spark occurring within the phone, you would have to extend the warning to every other electrical device, especially electrically noisy devices such the wiper motors in the car itself. In fact these internal sparks have nothing whatsoever to do with *static* electricity either. In short, I would lose the mobile phone stuff.

Otherwise

Traveller in Time discharging
"Anything that floats is a boat, as soon as it has a skipper it is a ship. (you would insult the captain by calling it a boat)"

That's better GB! I'm going to be a tiny bit pedantic and just say that the Lusitania didn't explode - it sank: explosions to me means that it fragmented into little bits, but you know what I mean. Also we know that the torpedo did penetrate the hold - no probably's there - but it "may have" set off a dust explosion.

I really like this entry. A great opening section which sets the scene, a nice explanation of static electricity, and packed full of useful tidbits.

"To move electrons from one place to another, rub two objects together (causing friction). " - well, that's just one way. Magnetic fields do the trick as do certain chemical reactions.

"At least until the electrons on the balloon wear off." - I wonder if there is a better way of saying this? The electrons themselves don't wear out. It would be my guess that they are transferred into the outside environment through the action of ions in the air, dust etc.

"many more women than men cause fires while refuelling". Not necessarily true. Check this out: http://www.snopes.com/autos/hazards/static.asp
You may be able to find extra useful information here to pad out your link. Unfortunately it also puts your "The Survey said" piece under the microscope, as it seems that this is a distortion of the real survey which is available through that link.

"Don't use your mobile phone (or pager) - leave it inside the vehicle or turn it off if it's on your person." Not true. That's an urban legend. The possibility of a static spark from a cellphone is remote in the extreme. http://www.snopes.com/autos/hazards/gasvapor.asp

Just one thing omitted, I think, and that is the Van De Graaf generator beloved of science students the world over. You stand on it and in a few minutes your hair is standing on end. This generator generates huge potential differences and can even be used to create mini-lightening discharges.

Well done!

W

I on't understand this:

'many more women than men cause fires while refuelling. The theory is that they are more prone to re-enter their vehicles during cold weather, build up a static charge and cause a dangerous explosion and fire when touching the pump again'.


In the UK at least, it's impossible to enter the car when the pump is still pumping fuel, as one has to keep one's hand on the trigger.

'Just one thing omitted, I think, and that is the Van De Graaf generator beloved of science students the world over. You stand on it and in a few minutes your hair is standing on end. This generator generates huge potential differences and can even be used to create mini-lightening discharges'.

Well, IMO this is an Entry about the dangers of static electricity. The v.d.G.G. is a way of deliberately creating it for useful purposes, and so would be an Entry of its own.

However, I do think it's worth pointing outy that static electricity has its uses as well as dangers. For e.g. electrostatic precipitators are used in the smoke stacks of coal-fired power stations to precipitate coal dust that would otherwise emanate at a rate of thousands of tons/hour; thus giving rise to particle pollution.

Ref women and cars: The reason that women are more prone to static socks than men can be blamed on their nylon tights (and stckings) - according to an AA report. Synthetic materials like nylon andpolyester are prone to producing S.E. and, as a result, women are more likely to be shocked by their cars. fURTHERMORE MANY OF THE CARPETS AND UPHOLSTERY IN CARS ARE ALSO MADE FROM SYNTHETIC FIBRES.

tHE BEST WAY TO EASE THE PROBLEM IS TO WEAR CLOTHES AND SHOES MADE FROM NATIURAL ( for shouting) materials like cotton or leather.
Periodic touching of the car's interior during a journey can help to discharge static before it can build up.

Anti-static sprays applied to the upholstery can also help.

Because more and more car interiors have little or no bare metal, some manufacturers now fit vehicles with a special button, which can be pressed to alleviate the build-up of static.


PS I once read this (in answer to 'Answers to Correspondents' in the Daily Mail, UK)

'Further to the earlier answer, an altar boy was taught in his class about S.E.. A typical boy, he wanted to test out the theory.

So, on Sunday, when he carried the communion plate, rather than picking up his feet he shuffled them on the carpet.
The first person receiving communion picked up the piece of bread with a yelp. By shuffling his feet on the carpet, the boy had effectively charged himself up.
Both he and the communion plate had become charged with S.E. The unsuspecting parishioner discharged the plate as he touched the metal edge.
I believe the boy was removed from his post.'

Many US pumps still have a mechanism to lock the pump filler in the open position while the driver cleans the windshield, checks the oil or does something else useful. These devices are being phased out and replaced gradually with fillers that require the driver to hold the pump constantly.

One can also jam a plastic gas cap into those fillers that lack such a device so that time can be more usefully during the refill process. For example, reentering the car to keep warm.

I always knew the UK was a more technologically advanced nation.

The MG and Lucas are the best evidence of that.