Let's start whit my favourite

I think electronics is modern magic, we carve little really specific drawings into a type of rock and add certain impurities and it controls things completly invisible to life and we can make it do math? That is what I call magic, but some people tend to insist its "physics".
These wont be in any particular order.

The Cathode Ray Tube, in few words what it does is shoot electrons at the screen which have a layer that glows when hit by electrons.
Where do the electrons come from? The incredibly named electron gun of course!