Date: Wed Feb 14 10:46:58 2007

Author: David Sturm

Subject: Re: Incandescent Bulb Destruction and Uses

Post: writes:
>Also, I will tap the threaded part with a hammer, which breaks the glass, and remove the bulb to show the filament and its connection to the base of the bulb. It can be interesting to predict how the filament from a high wattage bulb compares to a
>lower wattage one (length and thickness), and then take a look. It's tempting to plug in the bulbs afterwards just to show the rapid oxidation, since it's pretty hard to store them in that condition.

When breaking bulb carefully like this, it can be useful to have the power run through a variac, and find the voltage at which they burn out... some will function at really low voltages a bit longer. Of course, at usual line voltage, the burnout
can be somewhat similar to a magnesium flash bulb! I suppose this could be the po'folks version of the "Use Flash Bulb To Simulate Supernova". With a broken 3-way bulb, I guess you could have a sort of variable double supernova...

I'm not sure of a DCS number in the 5D20's, but I know one can also take a carefully broken bulb, and invert it into a clear container containing liquid nitrogen... I'm thinking this has been done at the summer Demonstration Workshop before, or in
one or more of the Public shows... Of course, only do it if you're experienced with liquid nitrogen demonstrations. I guess one can look it as a variation on 5D20.10.

David E G Sturm - - 1.207.581.1241
--Physics & Astronomy Instructional Laboratories
--Bennett Hall Lecture Demonstration Facilities
--Mainely Physics Road Show
Dept of Physics & Astronomy -- University of Maine
5709 Bennett Hall -- Orono ME 04469-5709