ELI5: Explain Like I'm 5
Examples: why are black holes so dense, net retention revenue, taylor's series, rocket engines, what is the difference between shia and sunni

Gope boards

A skateboard is like a piece of wood with four wheels on it that you can ride. A "gopro board" is a special kind of skateboard with a GoPro camera attached to it. The GoPro is a special kind of camera that you can use to take pictures and videos as you ride. With a gopro board, you can record your ride and share it with your friends. It's a fun way to show off your cool tricks and get to share your experience with other people.