Reference to Ground
When you think about it, most things in life are actually defined as a reference against something else. Let’s think about electricity for a moment.π€
Voltage is the difference in the number of electrons between a power source and a ground. It’s not that grounds have no electrons, they have many electrons, but grounds have more or less electrons compared to the hot side.Β β‘ Relatively speaking, a ground has a voltage of zero volts compared to the hot. It has electrons, but they aren’t referenced against the hot side. If you look at the wiring at your house, and it’s wired properly, the neutral wire will go out to a ground rod driven into the ground. The neutral and ground wire in most houses is connected to a single stake. You can stick a wire in neutral side, touch it with your bare hands (as long as it’s wired correctly). In contrast, if you do this on the hot side, you will quickly die, as deadly number of electrons will flow either to or from your bodies, as you are most likely connected electrically to the ground, as you are standing on the ground or something connected to the ground. π
You can actually hang off a high-voltage power line, and won’t get a shock if you don’t touch the ground, which the high-voltage wires are referenced against. Birds sit on high voltage line, and don’t even feel a tingle. π¦ There is no reference to ground. Squirrels can run on high-voltage line but if they touch the power pole that is connected to ground, they will be instantly fried. If you have an isolation transformer that is referenced to a return wire rather then ground, it’s actually safe to touch a high voltage hot wire while standing on the ground, as no current will flow, as there is no reference to ground.
That is not limited though just to electricity. When you think about it most things really are just references to other things they are compared to.π‘