Thursday, 1/29: Finding the Speed of Light

Over the centuries, many methods have been used to find, or attempt to find, the speed of light. Today we used a very simple method.

We start with an equation we've seen before for the speed of a wave: speed = wavelength x frequency

The frequency can be found written on the back of the microwave. Ours was f=2.4GHz or 2,400,000,000 Hz.

Next, we microwaved some candy bars for about 15 seconds (without the turntable). This produced melty spots that were half a wavelength apart (see notes). By measuring this, we were able to find the wavelength of the microwaves.

Your homework is to calculate the speed of light using f= 2,400,000,000 Hz and the wavelengths we found in class. Here are some sample wavelengths to use if you weren't in class:

0.12 m, 0.13m, and 0.15 m.

Those students that brought candy bars got to make s'mores with the leftovers. S'mores! Yay!

Notes:


Edit: Here is a good explanation of a similar experiment.