The ratio of the electric force to the gravitational force for two protons is a good way to get a numerical feel, but the intuitive "aha!" is what the demos are

The ratio of the electric force to the gravitational force for two protons is a good way to get a numerical feel, but the intuitive "aha!" is what the demos are trying to help with. There's a similar demo for showing the strength of atmospheric pressure. You can boil a little water in a soda can, and quickly invert it into a little bowl of water. The water vapor inside quickly condenses causing a startling implosion of the can. It gives an intuitive feel for what 1 atm actually is. You think of astronauts going to where they have to counteract that pressure, and what would happen on failure, and you think "holy shit." Then you think of James Cameron going to where the pressure is 1000 times as great, and what would happen on failure, and you think "holy fucking shit!!"