Is a light bulb that's burned out really "burned out"(Yet another from my employer's son)?

Question

I tried telling him this was a poor science fair topic, but since he's really good at procrastination, it's too late for THAT futile argument.
Please answer so a 6th grader can comprehend. Thank you.
Q.

Answer 1

There is no oxygen inside a lightbulb. There is only a small amount of inert gas inside. Without air the filament can not burn in the catch fire sense.

However the filament can evaporate so a thick tungsten wire becomes steadily thinner and more brittle. When it breaks that is often called burned out.

How this can be made into an interesting exhibit I have no idea.

Answer 2

A Light bulb has a wire called a filament.
When electricity goes through it, it gets so hot it glows.
Just like the glowing elements in a toaster! Only, it's much thinner and glows much brighter.
Ordinarily, it would burn or melt pretty quick. It's surrounded by a protective vacuum (inside the bulb) but will eventually break.
The wire starts out an even thickness, but one piece will be slightly thinner, and be slightly hotter. When this piece finally breaks it can leave a scorch-mark on the inside of the bulb.

With a clear bulb, you can see the broken filament. With frosted glass, you see the scorch mark. And if the mark is missing, gently shake the bulb- a broken filament wire will rattle.

Answer 3

It's hard to say, since the definition of burn is really quite vague.
http://en.wikipedia.org/wiki/Burn

Generally, no, bulbs do not "burn" out, using the a definition of burn as damage by fire or combustion. The filament inside of a bulb is isolated from oxygen via the bulb, thus preventing any oxidation, and thus preventing fire and combustion.

In the medical sense, a burn can be caused simply by heat, chemicals, or even cold. However, I don't believe this definition of burn applies to non flesh materials.

An interesting experiment could be shown what a bulb burnout looks like in the bulb, and when exposed to oxygen. We you break a bulb while it's running, the big flash you see is probably an explosion.

Answer 4

There is a wire that actually heats up so hot that it burns white hot...this is the actual light output that we see. It heats up that hot because it's specially treated, and it has electricity flowing through it. Over time, the wire (also called a filament) can burn out or break, and in turn, breaking the connection to the electricity flow. This will cause the light bulb to "burn out". I hope I've helped you. Best of luck to you.

Answer 5

If you take a close look at a light bulb, (before it's in the socket, please - save your eyes), you'll see a couple of curly-type things that come out of the base on a slight outward angle. At the top of these there is a slim piece of wire,called a filament, that connects the two.

A light bulb is "burned out" when that filament is burned out by the energy that is transmits.

Answer 6

Alrighty then...

There's a little wire thingie inside a light bulb. That's what makes the light when electricity goes through it. After a while, the wire thingie gives out. *poof* No more light. It "burns out".

Answer 7

yes the filament wire that lights up will after time either break or burn and break. That is generally the sound you hear rattling around when you shake a dead bulb.