Chapter 3 - Small children defy Newton

Durba reassured me about the capability of small children to push themselves around on chairs, without any part of their bodies touching the ground. All the teachers in the school she worked in knew about it, and considered it a nuisance. Reminding myself about my own childhood, and from my mother's point of view, I wrote:

Dangerous silence! What could that be?

What mischief is he up to now, let me see.

Not for one moment can I ever be free.

(We should never have come down that tree!)

It is, I am afraid, exactly as I thought.

You, young man, I have black-handed caught.

This art, has it been in kindergarten taught?

To paint walls with shoeblack yesterday bought!

Another time you woke me with chin deeply cut.

You had watched your father shave with eyes half shut;

Stealthily pulled the tablecloth, lifted the razor but

Then all your scheming backfired with mighty phut.

What was there in it for me, every time you fell?

Every time you cried, every time you were unwell?

Just the joy of doing what made the heart swell:

Being of use in golden days and of them, tell.

If only I could become a kid once over again! Yet, why not? I lifted my feet from the ground, and with my back and behind gave a backward push to the seat and rest of the chair I was sitting on, as powerfully as I could.

The chair moved! I swayed a moment or two to keep my balance, and then observed that the chair-body system had actually moved a few centimeters! If there had been less friction between the chair legs and the vinyl floor, I could have moved even more, I thought.

The man-chair system had apparently violated Newton's first law of motion! The movement had taken place without need for friction - in this case friction had the opposite effect, of retarding motion instead of making it happen, such as in walking or running.

I became restless. I knew that the above-mentioned experiment would not convey much importance to most physicists. It was not the same thing as moving a lunch box. Human involvement, creating such motion, diminished the significance.

How could I move a lunch box?

Could internal collisions involving electromagnets accelerating current carrying heavy conductors against the side of the container do the trick? I tried to make electromagnets, and failed. My personal resources were sorely limited. I had no laboratory, no workshop, no money, no technical support, and no friends apart from a mildly sceptical but supportive family who indulged me in my "mad scientist" phase. And I did not have much time, working full-time and doing the usual jobs of a family man.

My feelings were low. And then, once again, I thought of the meaning of the word life. One characteristic of life is motion. Cars, then, had life.

If you put a car in a container, and drive it against one of the sides, will the whole system move? I guessed it probably would.

Like a flash an idea came to my head. Why not put a remote-controlled toy car into a container? If the container was light as compared to the mass of the car, the whole system should move after collision.

"Balsa," I told my wife. "I need to make a light container with balsa wood."

Durba countered. "Why bother? Why not use Titli's old lunch box? That is of plastic, and will be quite as light." (Titli is my younger daughter.)

Brilliant. I told her about my plan. Immediately we went to the local toy shop and bought a red Porsche for twenty-nine dollars and ninety-five cents.

I placed the Porsche in the box, and using the remote control drove the car against the side of the lunch box. The system moved! I had beyond any doubt violated Newtons First Law of Motion for a system. I had moved what appeared to be just a body (closed lunch box) but which was actually a system, using internal force.

Could I keep on moving it? Frictional forces had stopped it. In outer space, there would be no such force, and the lunch box would have moved on for all time to come, I thought. I tried to bring the car backwards for another hit. But my control was not very good. The car reversed with about the same speed and hitting the rear wall, returned to near-about the initial position.

I put an inclined balsa ramp in the lunch box. The car would go up the ramp and hit the wall, and then slide back by force of gravity, with slight reversing applied. Some manual skill had to be employed to see that it did not hit the rear wall hard. I found my younger daughter far more adept at this task. (That particular model did not have powerful reversing, so attempts to drive it down the ramp and then reverse it up did not work very well.)

With this ramp, I could minimise the speed of the return hit of the backward moving toy car. As a result, with repeated hits, the lunch box staggered on forwards, on a go-stop basis.

So what, the family asked, not very impressed. If you take the car out of the box, and just drive it on the floor, it is so much more interesting. The car goes much faster!

You will all understand why it is so interesting in the next chapter.

Right now, let us make just one small correction to Newton's First Law of Motion. We just delete the word externally. And then... may Mother Nature be happy. Let the concept of motion deal with life, not death.

With shake of loose tresses, I herald the coming of Spring!

Trees wake up! Yawn, to your bare branches greenery bring!

Birds get active! Be brisk, flit about, preen, mate and sing!

Waters rush clear! Air be milder! Nourish, nurture everything!

These words are not just words. They are real, as dear bells that ring

With shake of loose tresses, I herald the coming of Spring!

Further note: Isaac Newton did not have a daughter who could play with remote controlled toy cars.