I recently read that there is a light bulb with carbon filament that has burned continuously for 105 yrs--?

Question

@ a fire station..How much longer will this bulb stay illuminated?And even if these bulbs are not as bright as some other types of bulbs.Why don,t citys around the world use this type in 'Some' street lights?so they could save on Energy ? I know they wouldn,t be right for All lights but in historical places it seems like they would be a good idea..Don,t they make this kind anymore?
> Question from my niece -4th grade this year <

I don,t understand~iF THE FILAIMENT IS MADE FROM A THICKER CARBON WIRE and it doesn,t cost alot to make it,why aren,t there more bulbs made this way?Where I live they have lots of OLD Street lights[for old style look I gues] It seems like they would last longer and look older and mostly cost less to use?My aunt said "l e d" lights are cheaper to make and use.But when I asked the Electric Man He said those lights are NOT led eighter.I thought if lights all over my town where like that One.The city would have more money for other things.And it would help save the earth.My city had a big celebration on earth day.and then I saw this light.It just seems like it would be better thing to do to me and my cousin. Thank you for talking about it with me.Annette.when I go home I,m sharing this with my teacher.I want my town to win Yahoo contest for greener city next time they have it.Will there be another one?When?

Answer 1

Yes there is such a bulb. In fact you can see it online in real time since a web cam keeps transmitting the feed.

No one can say how long it will go on. Actually, everything has an average life expectancy which is calculated after taking into consideration a large number of those things. This doesn't mean that there will not be specimens which will survive for extremely long times

For example, some people live to be 120 and beyond, but not everybody.

Electric bulbs are neither long lived nor energy saving. Much better are LEDs.

Answer 2

I seem to remember that the fire station is in Livermore, CA.

The formula for the life expectancy of electrical equipment is based on the Arrhenius equation. The basis for the equation is the temperature at which the item operates. Typically for every 10 degree centigrade rise in temperature, the life expecancy is cut in half. More electrical equipment is designed for a 55 degree C rise for 40 years. Obviously this bulb was so conservatively designed that its life expectancy is in the thousands of years. That does not make it energy efficient. It actually doesn't put out much light per input watt. The amazing thing to me is that there have been no electrical power outages. The system prodiving the electricity has not failed in over 100 years. That is what is truly amazing.

Answer 3

You can probably take a light bulb rated for 120 volts and run it at 30 volts and get it to last 100 years, too. A modern incandescent bulb is designed to get the maximum light intensity for the minimum wattage, but at the expense of filament life. For an equivalent light output on a 100 year lamp, you'd pay a huge penalty in electricity use.

Answer 4

The filament for the bulb is really thick! Highly impractical for common use. Fluorescent and LED bulbs are currently the most energy efficient.