Home Depot/ Radio Shack speed of light?

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Discussion Overview

The discussion revolves around methods to measure the speed of light using materials that can be sourced from Home Depot and Radio Shack. Participants explore various experimental setups and techniques, including historical methods and modern approaches, while considering the feasibility of these methods for educational purposes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant suggests using a mechanical interferometer similar to Michelson's method, involving a spinning mirror to sync outgoing and incoming light pulses.
  • Another participant recalls a lab experiment that utilized a fast oscilloscope, a function generator, and a laser and detector, questioning the availability of these items at Radio Shack.
  • A different participant mentions measuring the speed of light through standing waves of known microwave frequencies, indicating a method that could be applicable in a university setting.
  • One participant expresses interest in using a 60, 10, and 3-watt generator for ham bands to observe standing waves, questioning the safety of radiation exposure for students.
  • Another participant describes an experiment involving a transmitter and receiver setup to monitor voltage and identify standing wave patterns based on distance and wavelength.
  • One participant humorously notes the potential for an "edible lab," indicating a light-hearted approach to the discussion.

Areas of Agreement / Disagreement

Participants present multiple competing views and methods for measuring the speed of light, with no consensus reached on a single approach. The discussion remains unresolved regarding the best method to use with available materials.

Contextual Notes

Participants mention various experimental setups that may depend on specific equipment availability, safety considerations regarding radiation exposure, and the accuracy limitations of historical methods.

Who May Find This Useful

This discussion may be of interest to students, educators, and hobbyists looking for practical methods to measure the speed of light using accessible materials.

bblupton
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Home Depot/ Radio Shack speed of light?

Is there a way to measure the speed of light, to say 2 significant figures, using things purchased from Radio Shack and Home Depot? I've got a 200' hallway and front surface mirrors. Thanks, Bradshaw
 
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I believe Michelson used a mechanical interferometer (a spinning mirror and a prism) in his test. I'm not sure if this is how he did it, but if you vary the rpm of a spinning mirror, you can sync up the outgoing and incoming pulses of light to measure the time. You won't get any better than 1800s era accuracy, but it its a start...is this for a college project?
 
I recall a lab experiment using a fast oscilloscope, a function generator, and a laser and detector. (Can you get these at Radio Shack?) Try googling: "speed of light" AND oscilloscope .
 
I go to school at a cheap university, we measured the speed of light by setting up standing waves of known microwave frequencies. Google for standing waves.
 
Thanks for the standing waves idea. I have a 60,10,3watt watt generator for the 2m and 70cm ham bands. What is the apparatus and method of observing the standing waves? I wonder if 3 watts is too much radiation for students (and me!) Thanks, Bradshaw K1TE
 
The microwaves in our experiment had a wavelength of about 10cm (this is what is measured in the experiment). The apparatus consisted of a transmitter and a reciever, the distance between which could be varied. Monitoring the voltage in the receiver can tell you when standing wave patterns occur (when the distance between trans and reciever is an integer multiple of wavelength).
 
Thats great! And an edible lab as well! Thanks, Bradshaw
 

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