How to measure speed of light at home

Put a licorice bar into a microwave oven and walla - you can then measure the speed of light! From is Gadget:

Step 3: When microwave will be turned off. And licorice bar wont be hot, it will have this aspect (view photo above). Several places in the bar are more burnt than others, and there are places intacts (There are “valleys” in the wave). Then, take a ruler a measure distance between the center of this two “valleys”. In our case is about 6 cm.

Step 4: Turn over microwave and see wave frecuency. It is indicated in the technical features plaque. In our microwave this data is 2450 MHz. This means “megahertzs”. An “hertz” is number of oscillations in a second. In this way, “Megahertz” units are the inverse of the time, indicated by “s-1“.

Now, multiply by 2 distance measured before, and multiply again by 2.450.000.000 s-1. The result is surprising! : 12 × 2.450.000.000 = 29.400.000.000 cm/s =294.000 km/s … the speed of light!

(Thanks GeekGod)