Lecture 6 – Some impacts of measurement on life: and can we take it too far?
From the 1981 lecture programme:
In some instances, our ability to make very precise measurements has profoundly affected human thought, and even affected the character of life. The measurement of the shadows of sticks at Alexandria and Syene enabled Erathosthenes about 230 BC to estimate the circumference of the earth; and knowledge of this kind, combined with information from navigational instruments such as the compass, helped Columbus to keep direction on dark overcast nights, and thus led to the discovery of America. Tycho Brahe's attempts to observe the distance of a nova showed that it was as far away as the other stars, and thus that the remote heavenly bodies were not immutable, and his precise measurement of the positions of Mars led to Kepler confirming and extending the ideas of Copernicus about the solar system, and thus to the realisation that we are not at the centre of the universe. Joule's precise measurements of temperatures led him to discover the great principle of conservation of energy. The discovery by Lord Rayleigh that nitrogen prepared chemically was about one part in one thousand lighter than that filtered out from the air, led to the discovery of argon and hence of helium, on which much modern technology depends. And Aston’s measurement to one part in ten thousand of the relative masses of atomic nuclei led to the discovery of ways in which atomic energy could be released.
If there is time, we may pause to consider why sometimes the advance of science has depended on such very precise measurements, and at other times on very crude experiments such as those which led Rutherford to discover the atomic nucleus. And we shall see that, although appearing so very different in character, both kinds of experiments are part of the same process.
We shall also hope to look at two triumphs of modern technology which depend directly on our ability to measure and control mechanisms with precisions of better than one ten-thousandth of a centimetre. The first is the video disc for recording whole film programmes on a single disc, and the second the electronic microcircuit, which involves the manufacture and the positioning of stencils in which the electronic connections themselves may be less than one ten-thousandth of a centimetre across, and where millions of them have to be made at the same time. Without such precision of measurement, the microchip revolution could never have occurred. Properly used, it can greatly multiply the potential of the human race. But in evil hands, it could be applied for our destruction, and in thoughtless hands, it could create social problems such as unemployment.
If there is time, we may look at the dangers of trying to extend measurement too far. It is as well to recognise these dangers: but measurement has been, and continues to be, of enormous value to humanity.
About the 1981 CHRISTMAS LECTURES
From the 1981 lecture programme:
The Christmas Lectures at the Royal Institution started in 1826, and there have now been more than one hundred and fifty in the series; and yet none has previously been on the theme of this year's lectures, which is measurement. Perhaps this is because the measurement is so much part of human life that we tend to take it for granted; but if we are to understand how our modern world, with all its achievements and its dangers, has evolved, then we need to know what measurement is, the principles by which measurements can be made, and why their applications have been of so much importance in the advance of science and in the development of technology. And we also need not be carried away by the spectacular successes of measurements, such as awakening mankind to the huge store of energy in the atomic nucleus, or the microchip, or the control of space probes as far away as Saturn; for despite Plato's proud claim that 'man is the measure of all things' there are many qualities in life that are very difficult, if not impossible, to measure such as love or courage, and we should therefore be cautious about extending measurement beyond its proper domain. But within that domain, measurement is one of the most challenging, fascinating and rewarding of human activities: this is what the lectures are intended to show.
