Modern Mind: An Intellectual History of the 20th Century (19 page)

Einstein’s three great papers of that marvellous year were published in March, on quantum theory, in May, on
Brownian motion,
and in June, on the special theory of relativity. Quantum physics, as we have seen, was itself new, the
brainchild of the German physicist Max Planck. Planck argued that light is a form of electromagnetic radiation, made up of small packets or bundles – what he called quanta. Though his original paper caused little stir when it was read to the Berlin Physics Society in December 1900, other scientists soon realised that Planck must be right: his idea explained so much, including the observation that the chemical world is made up of discrete units – the elements. Discrete elements implied fundamental units of matter that were themselves discrete. Einstein paid Planck the compliment of thinking through other implications of his theory, and came to agree that light really does exist in discrete units – photons. One of the reasons why scientists other than Einstein had difficulty accepting this idea of quanta was that for years experiments had shown that light possesses the qualities of a wave. In the first of his papers Einstein, showing early the openness of mind for which physics would become celebrated as the decades passed, therefore made the hitherto unthinkable suggestion that light was
both,
a wave at some times and a particle at others. This idea took some time to be accepted, or even understood, except among physicists, who realised that Einstein’s insight fitted the available facts. In time the wave-particle duality, as it became known, formed the basis of quantum mechanics in the 1920s. (If you are confused by this, and have difficulty visualising something that is both a particle and a wave, you are in good company. We are dealing here with qualities that are essentially mathematical, and all visual analogies will be inadequate. Niels Bohr, arguably one of the century’s top two physicists, said that anyone who wasn’t made ‘dizzy’ by the very idea of what later physicists called ‘quantum weirdness’ had lost the plot.)

Two months after his paper on quantum theory, Einstein published his second great work, on Brownian motion.
²⁰
Most people are familiar with this phenomenon from their school days: when suspended in water and inspected under the microscope, small grains of pollen, no more than a hundredth of a millimetre in size, jerk or zigzag backward and forward. Einstein’s idea was that this ‘dance’ was due to the pollen being bombarded by molecules of water hitting them at random. If he was right, Einstein said, and molecules were bombarding the pollen at random, then some of the grains should not remain stationary, their movement cancelled out by being bombarded from all sides, but should move at a certain pace through the water. Here his knowledge of statistics paid off, for his complex calculations were borne out by experiment. This was generally regarded as the first proof that molecules exist.

But it was Einstein’s third paper that year, the one on the special theory of relativity, published in June, that would make him famous. It was this theory which led to his conclusion that
E=mc
²
.
It is not easy to explain the special theory of relativity (the general theory came later) because it deals with extreme – but fundamental – circumstances in the universe, where common sense breaks down. However, a thought experiment might help.
²¹
Imagine you are standing at a railway station when a train hurtles through from left to right. At the precise moment that someone else on the train passes you, a light on the train, in the middle of a carriage, is switched on. Now, assuming the train
is transparent, so you can see inside, you, as the observer on the platform, will see that by the time the light beam reaches the back of the carriage, the carriage will have moved forward. In other words, that light beam has travelled slightly less than half the length of the carriage. However, the person inside the train will see the light beam hitting the back of the carriage at the same time as it hits the front of the carriage, because to that person it has travelled exactly half the length of the carriage. Thus the time the light beam takes to reach the back of the carriage is different for the two observers. But it is the same light beam in each case, travelling at the same speed. The discrepancy, Einstein said, can only be explained by assuming that the perception is relative to the observer and that, because the speed of light is constant, time must change according to circumstance.

The idea that time can slow down or speed up is very strange, but that is exactly what Einstein was suggesting. A second thought experiment, suggested by Michael White and John Gribbin, Einstein’s biographers, may help. Imagine a pencil with a light upon it, casting a shallow on a tabletop. The pencil, which exists in three dimensions, casts a shallow, which exists in two, on the tabletop. As the pencil is twisted in the light, or if the light is moved around the pencil, the shallow grows or shrinks. Einstein said in effect that objects essentially have four dimensions in addition to the three we are all familiar with – they occupy space-time, as it is now called, in that the same object lasts over time.
²²
And so if you play with a four-dimensional object the way we played with the pencil, then you can shrink and extend time, the way the pencil’s shallow was shortened and extended. When we say ‘play’ here, we are talking about some hefty tinkering; in Einstein’s theory, objects are required to move at or near the speed of light before his effects are shown. But when they do, Einstein said, time really does change. His most famous prediction was that clocks would move more slowly when travelling at high speeds. This anti-commonsense notion was actually borne out by experiment many years later. Although there might be no immediate practical benefit from his ideas, physics was transformed.
²³

Chemistry was transformed, too, at much the same time, and arguably with much more benefit for mankind, though the man who effected that transformation did not achieve anything like the fame of Einstein. In fact, when the scientist concerned revealed his breakthrough to the press, his name was left off the headlines. Instead, the
New York Times
ran what must count as one of the strangest headlines ever: ‘
HERE’S TO
C
₇
H
₃₈
O
₄₃
.’
²⁴
That formula gave the chemical composition for plastic, probably the most widely used substance in the world today. Modern life – from airplanes to telephones to television to computers – would be unthinkable without it. The man behind the discovery was Leo Hendrik Baekeland.

Baekeland was Belgian, but by 1907, when he announced his breakthrough, he had lived in America for nearly twenty years. He was an individualistic and self-confident man, and plastic was by no means the first of his inventions, which included a photosensitive paper called Velox, which he sold to the Eastman Company for $750,000 (about $40 million now) and the Townsend
Cell, which successfully electrolysed brine to produce caustic soda, crucial for the manufacture of soap and other products.
²⁵

The search for a synthetic plastic was hardly new. Natural plastics had been used for centuries: along the Nile, the Egyptians varnished their sarcophagi with resin; jewellery of amber was a favourite of the Greeks; bone, shell, ivory, and rubber were all used. In the nineteenth century shellac was developed and found many applications, such as with phonograph records and electrical insulation. In 1865 Alexander Parkes introduced the Royal Society of Arts in London to Parkesine, the first of a series of plastics produced by trying to modify nitrocellulose.
²⁶
More successful was celluloid, camphor gum mixed with pyroxyline pulp and made solvent by heating, especially as the basis for false teeth. In fact, the invention of celluloid brought combs, cuffs, and collars within reach of social groups that had hitherto been unable to afford such luxuries. There were, however, some disturbing problems with celluloid, notably its flammability. In 1875 a
New York Times
editorial summed up the problem with the alarming headline ‘Explosive Teeth.’
²⁷

The most popular avenue of research in the 1890s and 1900s was the admixture of phenol and formaldehyde. Chemists had tried heating every combination imaginable to a variety of temperatures, throwing in all manner of other compounds. The result was always the same: a gummy mixture that was never quite good enough to produce commercially. These gums earned the dubious honour of being labelled by chemists as the ‘awkward resins.’
²⁸
It was the very awkwardness of these substances that piqued Baekeland’s interest.
²⁹
In 1904 he hired an assistant, Nathaniel Thurlow, who was familiar with the chemistry of phenol, and they began to look for a pattern among the disarray of results. Thurlow made some headway, but the breakthrough didn’t come until 18 June 1907. On that day, while his assistant was away, Baekeland took over, starting a new laboratory notebook. Four days later he applied for a patent for a substance he at first called ‘Bakalite.’
³⁰
It was a remarkably swift discovery.

Reconstructions made from the meticulous notebooks Baekeland kept show that he had soaked pieces of wood in a solution of phenol and formaldehyde in equal parts, and heated it subsequently to 140–150°C. What he found was that after a day, although the surface of the wood was not hard, a small amount of gum had oozed out that was very hard. He asked himself whether this might have been caused by the formaldehyde evaporating before it could react with the phenol.
³¹
To confirm this he repeated the process but varied the mixtures, the temperature, the pressure, and the drying procedure. In doing so, he found no fewer than four substances, which he designated A, B, C, and D. Some were more rubbery than others; some were softened by heating, others by boiling in phenol. But it was mixture D that excited him.
³²
This variant, he found, was ‘insoluble in all solvents, does not soften. I call it Bakalite and it is obtained by heating A or B or C in closed vessels.’
³³
Over the next four days Baekeland hardly slept, and he scribbled more than thirty-three pages of notes. During that time he confirmed that in order to get D, products A, B, and C needed to be heated well above 100°C, and that the heating had to be carried out in
sealed vessels, so that the reaction could take place under pressure. Wherever it appeared, however, substance D was described as ‘a nice smooth ivory-like mass.’
³⁴
The Bakalite patents were filed on 13 July 1907. Baekeland immediately conceived all sorts of uses for his new product – insulation, moulding materials, a new linoleum, tiles that would keep warm in winter. In fact, the first objects to be made out of Bakalite were billiard balls, which were on sale by the end of that year. They were not a great success, though, as the balls were too heavy and not elastic enough. Then, in January 1908, a representative of the Loando Company from Boonton, New Jersey, visited Baekeland, interested in using Bakelite, as it was now called, to make precision bobbin ends that could not be made satisfactorily from rubber asbestos compounds.
³⁵
From then on, the account book, kept by Baekeland’s wife to begin with (although they were already millionaires), shows a slow increase in sales of Bakelite in the course of 1908, with two more firms listed as customers. In 1909, however, sales rose dramatically. One event that helps explain this is a lecture Baekeland gave on the first Friday in February that year to the New York section of the American Chemical Society at its building on the corner of Fourteenth Street and Fifth Avenue.
³⁶
It was a little bit like a rerun of the Manchester meeting where Rutherford outlined the structure of the atom, for the meeting didn’t begin until after dinner, and Baekeland’s talk was the third item on the agenda. He told the meeting that substance D was a polymerised oxy-benzyl-methylene-glycol-anhydride, or n(C
₇
H
₃₈
O
₄₃
). It was past 10:00
P.M
. by the time he had finished showing his various samples, demonstrating the qualities of Bakelite, but even so the assembled chemists gave him a standing ovation. Like James Chadwick attending Rutherford’s talk, they realised they had been present at something important. For his part, Baekeland was so excited he couldn’t sleep afterward and stayed up in his study at home, writing a ten-page account of the meeting. Next day three New York papers carried reports of the meeting, which is when the famous headline appeared.
³⁷

The first plastic (in the sense in which the word is normally used) arrived exactly on cue to benefit several other changes then taking place in the world. The electrical industry was growing fast, as was the automotive industry.
³⁸
Both urgently needed insulating materials. The use of electric lighting and telephone services was also spreading, and the phonograph had proved more popular than anticipated. In the spring of 1910 a prospectus was drafted for the establishment of a Bakelite company, which opened its offices in New York six months later on 5 October.
³⁹
Unlike the Wright brothers’ airplane, in commercial terms Bakelite was an immediate success.

Bakelite evolved into plastic, without which computers, as we know them today, would probably not exist. At the same time that this ‘hardware’ aspect of the modern world was in the process of formation, important elements of the ‘software’ were also gestating, in particular the exploration of the logical basis for mathematics. The pioneers here were Bertrand Russell and Alfred North Whitehead.