# Homework Help: Help w/ determing the speed of light in marshmallow experiment

1. Jan 17, 2008

### lavendermoon

1. The problem statement, all variables and given/known data
need to know calculated value for the speed of light (m/sec) the following is what I have been able to do, if I can have a few examples of how to solve for the above and the percentage of error I will be set.

2. Relevant equations

distance 10 cm, 12cm, 9 cm
wavelength 20cm, 24cm, 18cm
frequency 2,450 MHz

Please show me how to get the value for the speed of light and the percentage error for each of these these are my results for the first trial I have two more trials but will be able to do them If I can get help with these, Thank you

3. The attempt at a solution

2. Jan 17, 2008

### Tom Mattson

Staff Emeritus
What do these quantities mean? What is a "marshmallow" experiment?

3. Jan 17, 2008

### lavendermoon

I had to nuke some marshmallows and measure the distances between the hot spots. then use the distances with the corrosponding wavelength (2x the distances), and the microwave frequency (2,450 MHz) to find the speed of light (m/sec) and then find the percentage of error. The experiment comes from Rober Stauffer, Jr. "Finding the speed of light with marshmallows" The Physics Teacher, vol 35, April 1997

4. Jan 18, 2008

### Tom Mattson

Staff Emeritus
That makes much more sense now!

For percent error, see the following page.

http://www.ric.edu/faculty/bgilbert/s3pcerr.htm [Broken]

Notice it makes reference to "accepted value". To compute the accepted value of the wavelength, use the accepted value of the speed of light, together with the frequency you were given. Note that you must know how wavelength, frequency, and wave speed are related in order to do this.

Last edited by a moderator: May 3, 2017
5. Jan 18, 2008

### lavendermoon

Ok, I will give this a try, thank you very much

Last edited by a moderator: May 3, 2017