Lateral Thoughts Physics World  

A natural physicist?

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I suspect that most physicists know someone like my neighbour Tony. Although Tony has not had the advantage of a formal scientific education, he has built up a wealth of knowledge in science in general and physics in particular by asking questions, listening carefully to the answers and, later, analysing and researching any points he hasn’t quite grasped.

Not long ago, Tony popped into my house for coffee and a chat. It was obvious that he had something to say, and finally he could contain it no longer. “I’ve been doing some experiments with a potato hanging on a string from the washing line!” he beamed. Not feeling quite strong enough to ask him why he had a potato hanging on a string, I mumbled “really” in reply. Undismayed, Tony continued with a mounting enthusiasm and excitement that reminded me of myself many years ago. “I’ve discovered that it takes the potato the same time to swing 20 tiny swings as it does to swing 20 big swings,” he said. “I timed it using my pulse because my GP told me that my pulse is remarkably constant and is always the same every time he measures it.”

This wasn’t the first time, of course, that I’d heard of intervals being measured in pulses rather than seconds. However, I didn’t want to dampen Tony’s sense of attainment, and I had to acknowledge his achievement in keeping track of a pulse count and a swing count simultaneously. “That’s a fine piece of research, Tony,” I whispered, and I gently introduced him to time periods, amplitudes and the formula for the behaviour of a simple pendulum.

Far from being discouraged that his “discovery” was not, in fact, new, Tony was engrossed. He quickly spotted the relationship between the only two variables in the formula. “So if I shorten the string, it will swing faster?” “Exactly so,” I agreed, nodding approvingly. “So what would be the effect if I used a massive potato, or I went into space where there isn’t any gravity, and surely it would swing forever if there wasn’t any air?” he continued.

These were all valid questions deserving answers and I was impressed by Tony’s awareness of things like air resistance. Before I could enlighten him, however, he was on his way over to the fireplace, where something had attracted his attention. I have a collection of “treasures” assembled during my life in physics, and they are now dispersed (frequently to my wife’s chagrin) around the house, garage, shed, greenhouse and garden. Tony had spotted my Newton’s cradle languishing on the hearth. “I’ve seen one of those in a science programme,” he announced. “Isn’t it something to do with the transfer of energy because all the balls are just touching to start with?”

As if trying to verify some point he progressively displaced and released an increasing number of balls, observing the results with obvious joy and pleasure. “It seems to slow down and stop quite quickly!” I briefly mentioned friction, heat and sound as sources of energy loss, but chose not to point out that in the ideal set-up the balls would be not quite touching. Nor did I introduce Tony to the concepts of conservation of momentum, or shockwave propagation through intermediate balls, or mention the fact that the actions he was observing had quite complex mathematical derivations. Topics for future coffee breaks, perhaps.

As Tony drained his cup, his eyes scanned the window ledge. “Wow, what’s that?” Following his gaze my focus ended up on another treasure: a Crookes radio-meter, its vanes gently rotating in the sunlight. He studied the device at close range for a full two minutes without speaking, before announcing “I think I know how it works! The black sides of the vanes absorb more of the sunlight than the white sides and that’s what makes them rotate. Is all the air taken out of the bulb though?” “Very impressive,” I replied. His theory was the early way of thinking, I explained, but in fact there isn’t a perfect vacuum inside the bulb. If there were, it wouldn’t work at all. Instead, the bulb contains a gas at very low pressure. Later theories, I added, were more complex and caused a lot of argument, animosity and unpleasantness at high level. Some big scientific names had a finger in this particular pie – Albert Einstein, Osborne Reynolds, Arthur Schuster and James Clerk Maxwell among them.

With his terrific sense of curiosity, ability to absorb information and his natural determination to find answers, he would probably have made a great physicist

Should I now mention thermal transpiration, I wondered? Perhaps not. “What did you say it was called?” Tony asked, nodding towards the bulb. “I didn’t,” I replied, “but it’s a Crookes radiometer.” “And who did you say invented it?” he asked, with an impish grin on his face. “I didn’t – and I’ll leave you to find that out for yourself, Tony,” I parried.

At this point, Tony remembered that it was time to feed his cat. After he left, it occurred to me that with his terrific sense of curiosity, ability to absorb information and his natural determination to find answers, he would probably have made a great physicist. As he shuffled across the road, talking gently to himself and frequently turning to wave in my direction, I wondered what Tony would be doing now if he, and not I, had enjoyed the kind of educational opportunities from which I had benefited. Preparing for a landing on some distant planet, perhaps, or even penning an article for a prestigious scientific magazine. As I watched Tony’s door close, I could see the first few words of his article floating before my eyes: “I suspect that most physicists know someone like my neighbour Peter…”