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Last Updated: Friday, 16 March 2007, 12:51 GMT
Age of enlightenment
By Jonathan Duffy
BBC News Magazine

Manufacture in China
The days of the humble light bulb are numbered, with plans to phase it out by 2011 in favour of energy-saving bulbs. Before consigning it to the dustbin, it's worth reflecting on how this cheap and disposable piece of technology has changed the world.

Asked to reflect on the recent backlash against Thomas Edison's pioneering "invention", his great-great-grand nephew strikes a positive note: "It's served us well for over 100 years", says Robert KL Wheeler.

But as the inverted commas suggest, this is not the first time the humble light bulb has been fought over.

Its very inception is a long-standing point of dispute among historians and engineers, with many, especially on this side of the Atlantic, crediting it to a Brit - Sir Joseph Swan.

Judging by Chancellor Gordon Brown's pronouncement this week to phase out these energy-sapping bulbs within four years, the debate seems destined to outlive the invention itself. Australia and California have already announced plans for a ban.

Yet in discarding the unassuming old light bulb, it would be reckless to overlook its impact. For a spurned piece of "obsolete" technology, it still shifts by the truck load - some 200 million a year are sold in the UK. It's hard to think of another electrical component that is more affordable, ubiquitous and disposable; its influence more profound, than the familiar incandescent tungsten filament light bulb.

Let there be light

Sure, it's about as environmentally sound as a Humvee with an oil leak, but then the bulb that millions of us flick on and off several times a day without so much as a second thought, is largely unchanged from the one that Edison patented 127 years ago.

HOW THE LIGHT BULB WORKS
Bulbs
Bulb filled with inert gas
Current heats filament to very high temperature
Filament becomes excited, releasing thermally equilibrated photons in the process
The light bulb, says Brian Bowers, former curator of electric engineering at the Science Museum, ushered in the electrical age in the home.

"The light bulb grew up with the electricity supply," he says, noting that in the 1880s, just after the bulb was invented, there were only a few, isolated power stations in Britain.

"It gave a purpose to electricity. It was what brought it along."

Artificial light pre-dates Swan and Edison's eureka moments. Candle light, oil lamps and, by the 1820s, gas lighting helped extend the day beyond the setting sun. But these were dirty, messy and smelly ways of illuminating a room, and, before gas, the light itself would be little more than a dull glow.

By the mid-19th Century, the light bulb had been solved in theory - all that was lacking was the technology to make it work. Several inventors were on the case but it was Sir Joseph Swan who figured out how to create a vacuum in the bulb - thereby starving the filament of oxygen so it would glow slowly, rather than burn out in a flash.

Edison's old bulbs
Edison originals: Two bulbs up for auction in 2006
Edison, meanwhile, cracked the carbonised filament, says Ian Peterson, of the Museum of Electricity, and set about making it marketable.

A glance at the diagram filed with his initial patent in 1880 (see below) shows how little Edison's light bulb has changed.

After thousands of years of man living by the natural rhythms of the sun, suddenly a room could be lit up with the flick of a switch. But with few houses actually wired up, the electricity industry used lighting to sell its benefits.

"Electricity sold itself on its cleanliness and simplicity, and also associated itself with modernity," says Frank James, professor of history at the Royal Institution.

At the same time, engineers were busy refining the light bulb, discovering tungsten glowed brightest. The final refinement came in 1934, with the inter-twining of two filaments to make a brighter lamp and a longer-lasting filament, says Mr Peterson.

"When you buy a light bulb today, you are buying precisely 70-year-old technology," he says.

Cover of darkness

At about the same time, the National Grid came online and by the end of the 1930s, half the households in Britain had electricity. Twenty years later, it was nearing 100%.

When you buy a light bulb today, you are buying 70-year-old technology
Ian Peterson
Today, no one pays a second thought to electric lighting, at least in the West. Our ability to banish darkness at the flick of a switch has upturned our lives, says Professor Roger Ekirch.

"It has transformed nearly a half of every day in terms of how we divide our time," says Prof Ekirch, author of At Day's Close: A History of Night-time. Before artificial light, night time was a time of "real and imagined fear".

The near-absolute anonymity of darkness accommodated horrific violence, says Prof Ekirch, as policing was largely impossible. The murder rate was five to 10 times higher in Britain, than today. Darkness was also the attendant of superstition and it's no coincidence that the intellectual enlightenment of the 19th Century accompanied the more tangible enlightenment.

But while "pre-industrial populations had thousands of years to adjust to nocturnal darkness," says Prof Ekirch, the light bulb has interfered with, perhaps even corrupted, the 24-hour circadian rhythm of our body clocks.

Two bulbs
Edison's patented bulb, left, from 1880, and a more modern incarnation
Before artificial light, we commonly experienced "segmented sleep" he says, in which one would slumber for a couple of hours in the late evening before waking for an hour or two at midnight only to sleep again through to sun rise.

"I'm no physicist," says Prof Ekirch, but he wonders whether this segmented sleep pattern explains many of today's sleep disorders. It's a theme that several academics have picked up since his book came out.

But Prof Ekirch says the light bulb has mostly been a blessing and suggests it is "arguably the greatest symbol today of modern progress".

So what would Edison have made of its impending banishment?

"I'd like to think he would think there's always a better way to do it," says Robert KL Wheeler. "Besides, I don't think the light bulb was his greatest achievement. The first recording of sound is his greatest contribution."


Add your comments on this story, using the form below.

Dont knock the lightbulb, using a 100W bulb indoors in a well insulated home gives 100W of heat which prevents your inefficient central heating boiler from cutting in. Rushing to change to energy saving bulbs may lower your electric bill but it is short sighted as the C02 production may be increased overall.
Al, Cirencester

Obliging people to buy energy-saving bulbs instead of ordinary ones is a good idea. But what about the spotlight type ones that are used so widely today? A kitchen ceiling can house quite a few spotlights, all controlled by one switch - 6 x 60 watt would give a total of 360 watts consumption. Low energy consuming alternatives for these are available as well via the internet. Will ordinary spotlight bulbs be discontinued as well?
Marilyn Cox, Oxford

I must admit that I occasionally marvel at the things humans have created. The Light bulb, Ball Point pens, Records and players etc. Some times simple ideas, and sometimes not. If something happened to our world and we lost our technology, would enough people remember how things worked to re-invent them? My partner thinks I'm mad having to know why and how things work, and where they came from. I believe that in knowing how things have come to be and how they work is a silent tribute to those great people who came up with the ideas.
Iain Record, Nottingham

About time! This seems a much more realistic approach than the current one of having building regs require fittings that can only take energy saving bulbs, at 10x the cost of a normal fitting that takes a normal energy saving bulb. Will the incandescent halogen bulbs that are so popular at the moment also be banned?
Mike, Cambridge

It's unfortunate that History has forgot one of the all time greatest inventors of our time, Nikola Tesla, the inventor of AC power and the man who brought electricity to the masses, along with hundreds of other things, with his alternating current. He invented the flourescent tube at the same time as Edison and new how inefficient the filament lamp was compared to the filament bulb, but sadly money and power decide what the people should have and his invention lay by the wayside for decades. It could be argued that Edison has done us more harm than good.
Barry McCusker, Glasgow

Whilst for general lighting the fluorescent bulb is on the whole better, will we still be able to buy the many decorative forms of bulb that are part of interior design?
Bob Peel, Maidenhead

I hope the old-fashioned light bulb doesn't disappear entirely, especially the little battery ones - they're ideal for getting into the understanding of electricity. Low energy light light bulbs run on much more difficult physics and chemistry. Also, I understand you can't keep switching low energy bulbs on and off, which is an invitation to leave them on in the bathroom which you may only visit for a minute at a time.
Robert H. Olley, Reading, Berks, UK

With "70 year" old technology I can have a bright light or any level of dimmed light just by turning a knob. With modern technology I can just have a dim light, that's progress for you.
Peter Horsfall, Farnborough

Can anyone tell me whether there are ecologically friendly lightbulbs available for use with dimmer switches and/or timers? Those I've seen don't suit either of these uses.
Helen, Kent, UK

Far from telling us that little has changed since the patent was filed, the diagram clearly shows that since then the whole design has quite literally been turned on his head! On a lighter note (sorry), before the light bulb, what did cartoonists draw above someones head to symbolise a good idea?!?
Colin, Edinburgh

This is a daft idea - it doesn't sound as if the total cost to society has been considered. What about the consequences of the manufacture and disposal of these "low-energy" bulbs? Instead of just glass and metal, which are easily recycled, they are loaded with electronics - so they "cost the earth" to manufacture. And what about dimmer switches? They don't work with low-energy bulbs. The only upside might mean the end of those terrible 500W "Bishops Rock" security lamps outside every home...
Stuart, Edinburgh

A fascinating and illuminating (!) article - easily the best thing I've read on the BBC site for months.
Keith, London, UK

I really do try to be as green as I can - recycling, rarely using my car, taking holidays in the UK - but I'm dreading the enforced use of low energy bulbs. They take ages to warm up and when they do, the light they give off is dull and cold. We have one in our flat and I never turn it on - maybe this is how they save energy?!
Sue, London

This is just another "frightener" to kid the public into speding more money to save the planet. Has anyone actually established how much more energy is actually consumed in producing these new bulbs? What are people with lights using "mini" bulbs (eg wall lights)supposed to do....scrap their light fittings? How can old age pensioners afford to restock their house with bulbs at 10 a throw? This would easily cost 100 per houseeven discounting the need to buy new fittings. Is there anything this government can do that doesn't cost everybody more and more money? Meanwhile, let us all contribute to the Olympic fund, yet another way of surreptitiously offloading the government's losses. Remember the Milenium Dome ???
Tony Bramwell, Oxfordshire

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