Bionics: What is a Volt?

I honestly find Bionics to be the toughest class to write about. Since it’s a survey course, there’s a lot of loosely-connected material that becomes difficult to summarize. So I’m ignoring what we actually talked about this week (how to generate electrical power from the ocean) to give my best explanation of what a Volt is.

A Volt is a unit of measure, abbreviated V. Just like meters or seconds, it measures an actual physical quantity, not absolutely, but relative to something else. For example, in a standard wall-outlet, one prong is 120V more than the other prong. 120V more what, though?

To understand what a volt is measuring, you have to understand about the E-field. You’ve probably heard of magnetic fields - many things generate them, from electrical wires, to refrigerator magnets. All of those magnetic fields generated by things combine to form a single ‘total’ magnetic field that describes all of the magnetic interactions of everything. Similarly, there is an electrical field that describes the electrical interactions of things. The field is stronger - I like to think of it as ‘higher’, but that’s not quite accurate - when something is strongly charged.

The Volt is a measure of difference in the potential of the E-field.

So how does this relate to electrons? Don’t they have something to do with this? If you have a bunch of electrons close together, that’s (almost) the same thing as saying that the E-field is many Volts high in that location. While some things that aren’t electrons (mainly photons) influence the E-field, mostly, a high E-field means a bunch of electrons, and vice versa. So back to our example: you have a bunch of electrons. They naturally repel each other. Why? Because they are ‘sliding down’ the E-field. Each electron is like a height of wave in the E-field. Naturally, the more stable position is for all the little waves to spread out. The taller the initial stack, the more quickly they fall down.

This is the same thing that happens when you stack marbles on top of each other in a gravitational field. The taller you make the stack before letting it go, the faster the marbles end up rolling away. That’s why higher voltages mean more power - and more danger of electrocution. The higher the stack (measured in Volts), the harder it hits when it falls.

So what’s really happening inside your wall is that a far-off generator is pumping one wire full of electrons, until the two wires are 120 Volts apart. When you plug something in, the electrons flow from one wire to the other, tumbling down the slope, and the device you plugged in uses the energy of the passing electrons to do something - light up, or power an amplifier, or what have you.

Next week, we’ll be talking about the next wild topic in the Bionics roller coaster - trees.