Well, first of all, there are actually two black boxes. One is called FDR, or Flight Data Recorder, and the other one is called CVR, or Cockpit Voice Recorder. They contain data that can be recovered after a plane has crashed, allowing the NTSB, or National Transportation Safety Board to investigate why the plane crashed.

The black boxes are situated in the tail of the aircraft, since that is the part most likely to survive a crash. In addition to that, the black boxes are made of super-strong materials capable of surviving shocks up to 3400 G (3400 times gravity), which equals an acceleration of about 32 km/s. It is also resistant to water, deep sea pressure, and fire.

The Flight Data Recorder contains a large array of flight data, such as airspeed, altitude, movement of the plane, fuel level, etcetera. It also records the temperature of the air outside the plane, the air pressure, the wind speed, and much more.

The Cockpit Voice Recorder contains every sound or voice that has been made in the cockpit for the last thirty minutes (sometimes up to two hours). It keeps overwriting itself so the hard disk does not need to be replaced.

So these two boxes are called the black boxes. In fact, they’re not black but orange. You can easily understand why. Imagine yourself a crashed plane. An area of about 50m² covered with airplane wreckage. What color would be the easiest to spot? That’s right, orange. The boxes are simply painted orange so they can be found more easily. But if they’re orange, why are they called black boxes? Well, that’s because all the other boxes, which control the airplane, are black. So when you say “black box”, you’re actually referring to the planes controls rather than the FDR and CVR.