Re: physics final project

[Larry Woolf <Larry.Woolf@GAT.COM>]

I'm partial to an investigation into the incandescent light bulb.
http://www.sci-ed-ga.org/modules/materialscience/light/index.html

Here are some relevant concepts:

Power dissipated in filament; I^2R
Color of filament as current is increased - additive color mixing
Ohm's Law (and increasing resistance of filament with increasing
temperature)
Wavelengths of light emitted by filament as current through filament is
increased
Light reflected or absorbed through glass housing
Why glass housing gets hot
Why glass housing stays hot after bulb is turned off
Why filament is a coiled coil
Conversion of electrical power dissipated in filament to light emission and
thermal energy (energy conservation)
Diameter and size and material of filament
Diameter and size and material of lead wires that support filament - want
high electrical conductance, low thermal conductance
Thermal conductivity issues -why vacuum
How 3-way bulb works -parallel circuits
Power dissipated in and electrical resistance of lead wires and filament
comparison - series circuits
Why cost is so low
Why glass is chosen for housing
Why vacuum or inert gas is used
Other competing technologies - e.g. sodium lamps, fluorescent lamps, halogen
lamps
Technologies to improve efficiency of incandescent light bulb -history,
present time
Why some lights buzz
Melting point, oxidation characteristics of tungsten filament wires
Motion of electrons in wire - acceleration between scattering events,
average drift velocity, time to travel through lamp


Larry Woolf; General Atomics; San Diego, CA 92121; Phone 858-455-4475;
www.sci-ed-ga.org


> -----Original Message-----
> From: Forum for Physics Educators 
> [mailto:PHYS-L@lists.nau.edu] On Behalf Of mitch foster
> Sent: Sunday, June 08, 2003 10:27 AM
> Subject: physics final project
>
> I'm a 10th grade conceptual physics teacher ("Physics First") 
> -- new = to the group.  I'm curious if anyone has any 
> ideas/suggestions for a = culminating or final project in 
> physics that somehow involves say all=  of a semester's main 
> concepts in one meaningful, tied-together, mult= iple part, theme?
>
> For example, a project that includes concepts of heat, heat 
> transfer,=  waves & vibrations, sound, light, and electricity 
> & magnetism.
>
> Any suggestions?=20