"So, you want to know how the light switch makes the bulb work, do you?"
"I do, yes. I can't figure it out. It's
something to do with electrickery, I think?"
"OK. It's pretty simple. Right, you see this switch here on the wall?"
"Yep."
"Great. Now, on the other end of the switch, inside the wall, there is a string. It runs up the wall inside a little tube, all the way across the ceiling, and down into that light over there. Got that?"
"With you so far. Seems reasonable."
"
Inside the light bulb there is a little pixie."
"A
pixie?"
"Yes. Only a tiny one, but it's there."
"...All right, I think I can see something that might be a pixie in there."
"They're
very small and that's a frosted bulb, so you'll have to take my word for it. So, the string goes into the bulb, and ends up tied onto one of the pixie's legs. Not too tight, that would be cruel, but it's not coming off. The pixie is strapped into a teeny tiny little seat. What do you think happens when I flip the switch like this?"
"The... string pulls on the pixie?"
"
Exactly! Yes, the string pulls on the pixie. And what do you think that
does to the pixie?"
"Um..."
"I'll tell you. It gets
really annoyed."
"Well, that seems only sensible..."
"I know. And an annoyed pixie gets very,
very active. It starts flapping its wings like
crazy."
"OK...?"
"It flaps its wings
so hard, in fact,
that they start to glow!"
"Really?"
"Yes. It's just like when you blow on a fire, right? Lots of air motion, you get a glow. A bright one."
"And
that's where the light comes from!"
"That is indeed where the light comes from, yes. I do this, the string gets pulled, all the way up there, across there, down into there, and bob's your uncle, the pixie gets annoyed and light comes out. See? Perfectly logical and straightforward application of String Theory."
"Hey, I've heard of that! I was
wondering what it was. I wish the people on the TV could explain things as clearly as you do!"
"Well, I
am an engineer, I know how to tell non-engineers about my field."
"And why does the bulb finally stop working?"
"The pixie dies. Because it doesn't get fed."
"...Poor little thing."
"Meh, pixies breed
really quickly. If we didn't put them in bulbs we'd be overrun with the damn things."
"Fair enough. While you're here, can you explain how the toaster gets hot?"
"Sure. Have you heard of glow worms...?"
