Using a dish full of marshmallows. We’re doing this with my oldest kids, and while I was reading up on it, I had to laugh out loud at the following:
…now you have what you need to measure the speed of light. You just need to know a very fundamental equation of physics:
Speed of a Wave (c) = Frequency (f) x Wavelength (L)
The distance between the melted sections of the marshmallow is in fact L/2, because there are two nodes for each wave (see animation). So if you have measured 6cm and your oven operates at 2450 MHz, then your measured speed of light is (0.12 x 2450,000,000) 294,000,000 metres per second.
The agreed value of the speed of light through a vacuum is 299,792,458 metres per second. See how accurately you can measure it? what could you do to make the experiment better, and thus get a closer answer?
IMHO, we need more published security metrics (and risk analytics) that don’t worry about those few million meters per second, and focus rather on the cleverness of using marshmallows and microwaves.