It's simple, and makes the concept of "generating" electricity accessible. If you spin a coil of copper inside a magnet, you push electrons. (You do not, of course, create these electrons anymore than you create the magnets or the wire.)
If you put some resistance in the path of these electrons, say, a light bulb, you need to crank much harder to spin the coil. Again, you can feel this. You are converting mechanical energy into something that "pushes" back.
It takes a fair amount of force to brighten up a reasonably sized bulb.
If a child learns nothing more than this, that to "create" electricity requires a push, that it's not magic, that you don't get electricity for nothing, she's a step ahead of most adults.
***
When I crank on the generator, I breathe a little harder as my muscle cells are called on to work. My cells burn up organic molecules, breaking down into carbon dioxide, using oxygen to catch the remnants of these molecules, spent electrons, in the depths of my mitochondria.
When I crank on the generator, the concentration of carbon dioxide in my room rises a tiny bit--the same carbon dioxide implicated in global warming.
When I crank on the generator, my muscles warm up a little bit--when I convert chemical energy into mechanical, I am less than 100% efficient. The heat I lose no longer serves me.
When I crank on the generator, I make energy increasingly less useful, energy captured as bonds by plants, now released as mechanical energy by me, so I can see photons emitted from the lamp. It took a bucketload of sunlight to produce a thimble's worth of incandescence.
A young child does not need to know any of this to know that generating electricity requires a push, and that the more electricity you need, the more push you must provide.
***
I remember learning about electric generators--it was a classic mid-20th century 16 mm film, moving images of the Hoover Dam with a sonorous male (always male) voice extolling our country's technological virtues.My brain whirs with the clickety-ckickety of a 1963 projector when I think of dams. Children are that impressionable....
A huge dam with huge turbines generated huge amounts of electricity. Somehow that juice got to the wall. It cost nothing because rivers were meant to be damned.
In junior high, my class visited the Oyster Creek nuclear plant, and again we learned about huge turbines generating huge amounts of electricity, clean energy, so safe school children wander within yards of a nuclear reactor.
.
Turns out most electricity generated in the States comes from burning coal, a process remarkably similar to the way I extracted energy from last night's clams. Oxygen strips off electrons from unstable organic molecules, coal and clams to carbon dioxide and water. I do it in a lot more steps, or else I'd spontaneously combust, but the end result is the same. The universe has smaller, more stable molecules, and useful work can be done.
Either way, something had to put the unstable molecules together in the first place. Both coal and clams rely on the nuclear furnace just under 100 million miles away, both coal and clams rely on plants to do this. You don't get something for nothing in the natural world.
***
This is a Chevy Volt. It is an electric car.
You can plug it into your wall and pretend it's green. Or you can start thinking about where things come from, where things go.
If giant hands holding up the Earth assuage whatever feelings you might have as we plunder the planet, then we get the planet we deserve. Nothing comes from nothing.
GM is depending on your ignorance (and your guilt) to shell out over $30,000 for a car.Before you do, come on by B362, and I'll let you crank on our class generator for a bit.
You're an adult now--time to give up magical thinking.
We can argue about the efficiency of coal-generated generating plants vs. gasoline engines, about the relative costs of charging a car during peak or off hours, about the carbon cost of making huge batteries, about the break point (likely around 80k miles) where a Volt may be greener than your Daddy's Oldsmobile, about the risks and benefits of dams, of nuclear rods, of dams, of wind, of solar, of tidal generators.
And these could be interesting discussions....
If you don't believe in magic
First photo from Old Pinawa self-guided tour online brochiue here
Posts
