I keep watching this video and it keeps blowing my mind.
Every time you need to navigate from point A to point B, your GPS guide performs a little calculation involving a) outer space, b) atomic clocks, and c) quantum mechanics. As a gadget blogger, I'm naturally interested in the inner workings of all the various devices that make up our lives, but I've always thought of GPS as this Whovian mystery -- it's all some wibbly wobbly timey wimey stuff. Basically, it's beyond my comprehension.
But this five-minute TedEd video does a good job convincing me otherwise. Basically, it's all about distance, the speed of light and time. Throw in some Planck's constant, satellites, and some Caesium 133 and you're ready to calculate distances anywhere on Earth. Take a few minutes to watch the full thing, and let your brain get linebacker blitzed with some serious knowledge. [TedEd]