Lets Measure Speed of light using Chocolate 😅🍫

 Need  a microwave, ruler, bar of chocolate .

(Better to take a  longer  bar of chocolate )

Take the turntable out of the microwave. We don't want uniform heating of Chocolate . You need the chocolate to stay still whilst you heat it.

Put a plate upside down over the thing that rotates the turntable . 

Now place the bar in the microwave and turn the microwave on .

It will take some 20 - 40 sec when chocolate will start melting in two or three places .

Now its time to take out chocolate and measure carefully the distance between one hot spot to another hot spot .

A hot spot is where the chocolate is starting to melt or is more melted than rest of the other portion .

Now the Calculation part 

Measure the distance between two melted spots and get  the half of the wavelength of the microwaves. Then multiply the distance by two to get a whole wavelength.

Frequency : I got it from specifications of my oven used ie 2450 MHz

Speed of light : 2 x 6 x  10^-2x 2450 x  10⁶

                     = 2.9 x 10⁸ m/sec