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SCIENCE FILE | MIND OVER MATTER

A Smooth Life Without Resistance Just Wouldn't Work

October 19, 2000|K.C. COLE

My friend the physicist used to get very angry with people who wouldn't argue with him. He thought you couldn't make any progress pushing the boundaries of understanding if other people didn't push back. He knew that pushing back was an essential part of pushing onward.

Certainly, pushing back is a vastly underrated force. People wish their lives could run smoothly without resistance, just as engineers wax enthusiastic about superconducting power lines that carry electricity friction-free.

We forget that, without resistance, life would be unlivable. And it's not just a matter of saying "no" to drugs or laying down the law for rebellious teenagers or 2-year-olds. Without resistance, we wouldn't be able to dance, play golf, or even blow-dry our hair. We think of resistance as an impediment, when in fact it's a driving force.

Consider even something simple, like walking. If you've ever slipped on a banana peel or skidded on an icy patch of road, you know the hazards of having your usual source of resistance suddenly removed. You can walk forward only because the street pushes back. You might think this is not rocket science, but, in fact, it is. A rocket can race forward only because something--if only hot air--is racing backward with an equal and opposite force.

For that matter, it's pushing back that allows you to push on anything. Pound the desk with your fist and it hurts because the desk pushes back; pound a marshmallow and nothing much happens, because marshmallows can't push back. In fact, it is physically impossible to hit anything (or anyone) harder than it can hit you--which is a good thing to remember the next time you're deciding whether to punch a wall or a pillow.

Without resistance, the world as we know it wouldn't exist: It's resistance that makes toasters and hair driers hot, that powers the recoil of the golf ball from the club, that propels the ballerina in her multiple pirouettes.

And that's only the beginning. Without a pervasive pushing back, we wouldn't have matter at all. Normally, we think of matter as that which has mass, and mass is defined by inertia. The harder something is to push around--that is, the more it pushes back--the more massive it is.

Where does this resistance to motion come from? Why are sofas harder to push across the floor than shoes?

Physicists believe that particles pick up mass as they slog their way through an invisible cosmic molasses known as the Higgs field. If it weren't for the resistance of this unseen stuff, everything would travel at the speed of light and particles of matter would never slow down; they'd never have the heft to clump into atoms or anything else.

So, pushing back is useful as well as inevitable. It's also a lot harder than most people think. We often equate pushing back with doing nothing--like a wall that just sits there as a car crashes into it. Like the ease implied in the expression: "Just say no."

Nothing could be further from the truth. In terms of the energy required, there is no difference between accelerating and decelerating, a start up and a stop down.

This is a hard fact of nature that NASA scientists face continually. Say they want to land a spacecraft on Mars. Obviously, they need enough fuel to fight Earth's gravity and blast the rocket into space and on to Mars. But they also need an equal amount of fuel to slow the spacecraft down to a stop before it reaches the planet's surface.

This is a good thing to remember the next time you're struggling to quit a bad habit. Whatever energy you put into creating the habit is exactly the amount of energy you will need to put it to a stop.

Pushing onward and pushing back are two sides of a coin. One without the other is as unthinkable as one hand clapping.

Or as Paul Hewitt, author of "Conceptual Physics," often puts it: "You cannot touch someone without being touched in return."

*

Cole can be reached at KC.Cole@latimes.com

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