# Home Depot/ Radio Shack speed of light?

• bblupton
K1TEIn summary, Bradshaw believes that there is a way to measure the speed of light, to say 2 significant figures, using things purchased from Radio Shack and Home Depot. He also suggests trying to find information on standing waves on Google.

#### bblupton

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

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).

Crosson said:
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.

I went to a cheaper university and we use a microwave to make the standing waves and marshmallows as the detector. Incredibly you can do better than 2 sig figs if you know the freq. of the oven typically 2.65 GHz. Google marshmallow speed of light on google & you will find many descriptions of this. Just be sure to use a paper plate and to take the turn table out of the microwave when you do the experiment.

mmwave.

Thats great! And an edible lab as well! Thanks, Bradshaw

## 1. What is the speed of light at Home Depot or Radio Shack?

The speed of light is a constant value that does not change, regardless of location. It is approximately 299,792,458 meters per second in a vacuum.

## 2. Is the speed of light affected by the environment at Home Depot or Radio Shack?

The speed of light is affected by the medium it travels through, but in Home Depot or Radio Shack, the environment is not significantly different from a vacuum, so the speed of light remains the same.

## 3. Can I measure the speed of light at Home Depot or Radio Shack?

Technically, yes, you can measure the speed of light at any location. However, it requires specialized equipment and careful experimentation to accurately measure the speed of light.

## 4. How was the speed of light first measured?

The first successful measurement of the speed of light was done by Ole Roemer in 1676 using observations of the moons of Jupiter. He noticed that the eclipses of the moons appeared to be delayed when Earth was farther from Jupiter, and used this information to calculate the speed of light.

## 5. Can the speed of light be exceeded at Home Depot or Radio Shack?

Based on our current understanding of physics, the speed of light is the maximum speed at which anything can travel. It is not possible to exceed the speed of light at Home Depot or Radio Shack or any other location.