My teacher once joked about sticking graphite into an electrical socket to see a bright light. What happens?

Question

He's a chemistry teacher, yet very sarcastic (great combination). He said if you tape down all the circuit breakers, and then stick a piece of lead (graphite from pencils) into an electrical socket, you'd see a bright white light, and then everything will burn down and you will be dead(?) That's part of the joke as well, since bright lights are usually "seen" by near death people. What exactly would happen were someone to actually do that? Is it like an arc flash? What is that as well?

Answer 1

I guess that your chemistry teacher was teaching about element carbon and its many structural forms. Graphite is an allotrope of carbon that can conduct electricitỵ  If you held a piece of graphite and sticked it into an electrical socket, you would be electrocuted to death before you could see any bright white light.

Answer 2

Well every circuit has a weak point.  Usually we make a fuse or a circuit breaker the weak point.  If you disable that safety, the current will go up until something somewhere overheats and breaks the circuit.  Yes, there will certainly be a flash of light as you close the circuit.  The lead probably will have more resistance than anything else in the circuit, so it will dissipate most of the energy.  Go try it.

Ask an electrician, but I suspect that there is probably something like a neighborhood circuit breaker that will black out your block neighborhood if it draws too much current to keep from crashing a much wider area.

Answer 3

I have seen people do this with jumper cables off a car battery, attached to the ends of a pencil lead (which is, of course, graphite and not lead).  It's very bright, in principle it's the same thing as the old graphite filaments used in light bulbs a long time ago.

It's supposedly an emergency light source for roadside mechanic work, but it's not really very useful for that.  Too bright and too dangerous of a thing to just lay next to you while you crawl under your car.  More of a neat MacGuyver trick to show your friends than anything.

I've never tried it myself.

Answer 4

I do not know if it would result in a "bright white light" especially if you were holding on to it with your hand.  Graphite is a conductor, so there is a good chance that you would become part of the circuit.  Taping down the circuit breakers would prevent them from tripping do to the short circuit the would occur.  It might be you that lights up.  DON'T TRY IT.  Ask the teacher to try it himself in class.  He might just be dumb enough to do it.

Answer 5

With all the above caveats in mind, you could probably make a carbon arc from two pieces of graphite, although I've only done it with carbon rods from (now old-fashioned) non-alkaline primary cells. It's an extremely bright light which exists only in the plasma between the tips of the rods, and actually is better made with a lower-voltage DC source such as a car battery, which also offers the advantage that you don't die. Typically you first have to "strike" an arc by momentarily touching the tips together, then separate them some. Carbon arcse were the primary source of light for aerial searchlights during WWII and were also used in theatrical and movie lighting.