Home experiments to derive the speed of light? Are there any experiments I can do to derive the speed of light with only common household tools?
 A: I can't think of a way to do it with "common household tools" but if you have an oscilloscope, a laser diode, a couple of photo-sensors, a beam splitter, you can do it.  All of these things are readily available from science supply/hobby stores online, but not usually in most homes.
Set up the laser diode to hit the beam splitter and be split into two beams.  Set up the two beams so that they hit two photo-sensors, but make one of the photo-sensors exactly twice the distance from the beam splitter as the other.  This will create two separate paths for the light, one twice as long as the other.  Run the output of the photo-diodes into two channels of the oscilloscope.  Switch on the laser diode, and you should see two pulses on the o-scope, one from each of the two laser diodes.  The difference between them is the time it takes the light beam to travel the distance of the difference in the two paths.
The reason to do it this way is accuracy - if you only had one beam, and your photo-diode took, say, 1 microsecond longer to turn on than what was in the documentation, or your laser were slow to turn on, then you would get very inaccurate results.  But with two beams, those errors cancel each other out, and so all you're left with is the time of the light.
A: There is a trick I have heard about before but never tried. The basic idea is to put a mars bar in a microwave oven for a short amount of time. First you remove the turntable, so the chocolate bar stays stationary. Then you turn the microwave on just long enough for the chocolate to start to melt. It should melt at the nodes of the standing field. You simply measure the distance between the nodes, and multiply by the frequency of the microwave oven to obtain the speed of light. There is a YouTube demonstration (by a kid) here.
A: Those laser tape-measures operate in an interesting way, that relies on the speed of light to determine distance. So conversely, if you have a known distance, then with the same equipment you should be able to estimate c.
What the tape measures do is modulate the intensity of the outgoing laser according to the intensity of the reflected light. It's basically an oscillator whose frequency depends on the optical propagation delay. The commercial products use the resulting frequency to determine a distance to display.
If you can get at the oscillator output, and set up to measure a known distance, you should be able to estimate c as the frequency in Hz times the round-trip distance in meters.
A: Perhaps a Fizeau inteferometer:
http://en.wikipedia.org/wiki/Fizeau_interferometer
Most of that should be in range of a keen amateur but I'm not sure what you use as a beam splitter without just buying one though.
A: I think the simplest would be to use an RF oscillator, a receiver to determine its frequency and Lecher wires (i.e. a pair of parallel wires) where the nodes of the standing wave are determined using an RF voltmeter. See http://en.wikipedia.org/wiki/Lecher_lines .
This was one of the experiments in an electronics kit which I had in my youth. The length of the Lecher line was about 5m and the frequency of the oscillator was about 100Mhz using just one transistor in a common base circuit.
As a variation it is also possible to change the frequency and measure how much the nodes have moved.
A: You could find a capacitor and read of its capacitance, alternately build one and measure it, and measure its dimensions. Now you can get a good estimate on the permitivity of vacuum, epsilon.
There are possibly other intricate ways to measure this number.
The speed of light is then given by a relation involving another number, the vacuum permeability, µ , which needs no measuring as it is defined.
This relation can be derived from Maxwell's equations.
$c=\frac{1}{\sqrt{\varepsilonµ}}$
A: With a clock and a telescope you could repeat Rømer's determination of the speed of light.
A: You might also want to try the rotating mirror method, of Léon Foucault. It is detailed here and here. The only difficult part is the rotating mirror, but it could probably be done with a drill.
A: Didn't the amateur radio guys (Hams) once launch a ballon like reflecting satellite?   Is it still in orbit?   Even at a few hundred kms, the delay would be in the ms.  Maybe the ISS is partly reflective.
A: What about a doppler shift method?   A doppler speed radar or lidar gun might have all the necessary components, for its logic to be reversed.  Here's one for instance, ready for disassembly.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300374815766&rvr_id=169891150704&crlp=1_263602_304642&UA=M*S%3F&GUID=0537e92612c0a06456359f45ffd1174f&itemid=300374815766&ff4=263602_304642#ht_2332wt_979
A: Has anybody a pointer to the Kinect patent?? the device of the XBox measures distance using reflection of infrared light, so for sure it depends on a finite lightspeed to work.
