A Brief History of Science with Levity Page 5

  During his early career, Tesla briefly worked with Thomas Edison before the two parted ways. Edison did not understand AC theory, phase angles, power factors and other basic knowledge required in order to design an AC power transmission system. In order to transmit large amounts of power over long distances the only efficient way is to use very high voltages. This is because the power you can transmit is the product of the voltage times the current, and the size and weight of the power cables required are dictated by the current that they need to carry.

  Therefore if you can increase the transmission voltage by 1,000 times, the cross-section of the conductor required to transmit the power can be reduced by 1,000 times. This principle is in worldwide use today, where main electricity transmission lines operate at several hundred thousand volts.

  These very high voltages must be reduced to manageable levels before they can be used by industrial and domestic consumers. The only way to do this efficiently is by the use of transformers, which we are all familiar with in electricity substations and on local distribution poles. In order to change the voltage of DC power, devices such as DC-AC invertors or rotary converters must be used, which are both expensive and not that efficient.

  These devices convert the DC power into AC which is required for the voltage conversion process. It is therefore difficult to understand why Edison did not want to generate his electricity as AC power in the first place.

  Tesla’s interest in electrical invention was likely sparked by his mother, Đuka Mandić, who invented small household appliances in her spare time while her son was growing up. Tesla’s father, Milutin Tesla, was a priest. After studying in the 1870s at the Realschule, Karlstadt, the Polytechnic Institute in Graz, Austria and the University of Prague, Tesla began preparing for a trip to America.

  Tesla travelled to the United States in 1884, and soon began working with Edison. While Edison was a power figure who focused on marketing and financial success, Tesla was commercially out-of-tune and therefore somewhat vulnerable. Tesla was however an extremely pivotal engineer, who pioneered some of history’s most important inventions. His 1891 invention, the “Tesla coil”, is still used in radio technology today.

  On the AC electrical system alone, Tesla held forty basic US patents, which he later sold to George Westinghouse, an American engineer and businessman who was determined to supply the nation with Tesla’s AC system. He would succeed in doing just that, not long after purchasing Tesla’s patents. Around this time, conflict arose between Tesla and Edison, as Edison was determined to sell his direct current system to the nation. According to the Tesla Memorial Society of New York, Tesla and Westinghouse ultimately won out because Tesla’s system was a superior technology, offering greater progress to both America and the world than Edison’s DC system. Outside of his AC system patents, Tesla sold several other patent rights to Westinghouse.

  At the 1893 World Columbian Exposition held in Chicago, Tesla conducted demonstrations of his AC system, which soon became the standard power system of the 20th century and has remained the worldwide standard ever since. Two years later, in 1895, Tesla designed the first hydroelectric power plant at Niagara Falls, a feat that was highly publicised throughout the world.

  Around 1900, nearly a decade later and after inventing the Tesla coil, Tesla began working on his boldest project yet. He planned to build a global communications system using large electrical towers, for sharing information and to provide free electricity transmission throughout the world. The system, however, never came to fruition. It failed due to financial constraints, and Tesla had no choice but to abandon the Long Island, New York laboratory that housed his work on the tower project, Wardenclyffe. In 1917, the Wardenclyffe site was sold, and Tesla’s tower was destroyed.

  In addition to his AC systems and other pioneering work, throughout his career Tesla discovered, designed and developed ideas for a number of other important inventions. Most of these were officially patented by other inventors, including the dynamo and the induction motor. He also made great advances in the development of radar technology, X-ray technology and the rotating magnetic fields used in most modern AC equipment.

  In the same year that Nikola Tesla was born, another great physicist and engineer named Joseph John Thomson was born in Manchester, England. His fundamental discoveries regarding cathode rays were the precursor to all future electronic equipment development up until the discovery of semiconductors, and the era of the transistor and the silicon chip integrated circuit.

  Thomson was awarded the 1906 Nobel Prize in Physics for the discovery of the electron, and for his work on the conduction of electricity in gases. He was knighted in 1908 and appointed to the Order of Merit in 1912. In 1918 he became Master of Trinity College, Cambridge (strange how they tend to get the great physicists from Manchester University) where he remained until his death. He died in 1940 and was buried in Westminster Abbey, close to Sir Isaac Newton.

  In 1897 Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, and thus he is credited with the discovery and identification of the electron, and in a broader sense with the discovery of the first subatomic particle. Thomson is also credited with finding the first evidence for isotopes of a stable (non-radioactive) element in 1913, as part of his exploration into the composition of canal rays (positive ions). He invented the mass spectrometer.

  Several scientists, such as William Prout and Norman Lockyer, had previously suggested that atoms were built up from a more fundamental unit, but they envisioned this unit to be the size of the smallest atom, hydrogen. Thomson, in 1897, was the first to propose that the fundamental unit was over a thousand times smaller than an atom, suggesting the subatomic particle now known as the electron.

  Thomson discovered this through his explorations on the properties of cathode rays. Thomson made his suggestion in 1897 following his discovery that Lenard rays could travel much further through air than expected for an atom-sized particle. He estimated the mass of cathode rays by measuring the heat generated when the rays hit a thermal junction, and comparing this with the magnetic deflection of the rays.

  His experiments suggested not only that cathode rays were over 1,000 times lighter than the hydrogen atom, but also that their mass was the same in whichever type of atom they came from. He concluded that the rays were composed of very light, negatively charged particles which were a universal building block of atoms. He called the particles “corpuscles”, but later scientists preferred the name electron.

  A month after Thomson’s announcement of the corpuscle he found that he could reliably deflect the rays by an electric field if he evacuated the discharge tube to a very low pressure. By comparing the deflection of a beam of cathode rays by electric and magnetic fields, he obtained more robust measurements of the mass-to-charge ratio that confirmed his previous estimates. This became the classic means of measuring the charge and mass of the electron.

  Thomson believed that the corpuscles emerged from the atoms of the trace gas inside his cathode ray tubes. He thus concluded that atoms were divisible, and that the corpuscles were their building blocks. To explain the overall neutral charge of the atom, he proposed that the corpuscles were distributed in a uniform sea of positive charge.

  This was referred to by some at the time as the “plum pudding” model, assuming that the electrons were embedded in the positive charge like plums in a pudding, although in Thomson’s model they were not stationary, but orbiting rapidly.

  Thomson constructed a glass tube with a near-perfect vacuum. At the start of the tube was the cathode from which the rays projected. The rays were sharpened to a beam by two metal slits. The first of these slits doubled as the anode, and the second was connected to the earth. The beam then passed between two parallel aluminium plates, which produced an electric field between them when they were connected to a battery.

  The end of the tube was a large sphere where the beam would impact on the glass, creating a glowing patch. T
homson pasted a scale to the surface of this sphere to measure the deflection of the beam. Note that any electron beam would collide with some residual gas atoms within the tube, thereby ionising them and producing electrons and ions within the tube. In previous experiments this space charge electrically screened the externally applied electrical field. However, in Thomson’s tube, the density of residual atoms was so low that the space charge from the electrons and ions was insufficient to electrically screen the externally applied electric field, which permitted Thomson to successfully observe electrical deflection.

  When the upper plate was connected to the negative pole of the battery and the lower plate to the positive pole, the glowing patch moved downwards, and when the polarity was reversed, the patch moved upwards.

  Thomson imagined the atom as being made up of these corpuscles orbiting in a sea of positive charge. This was his plum pudding model. This model was later proved incorrect when his student Ernest Rutherford showed that the positive charge is concentrated in the nucleus of the atom.

  CHAPTER 7

  While reviewing the previous sections of this book, I noticed that I had referred to James Clerk Maxwell as being born in Edinburgh, UK. I have now changed this to Edinburgh, Scotland. Although Edinburgh, UK is perfectly correct, many Scots are very sensitive about this kind of thing.

  I remember when Andy Murray (originally from Glasgow) brilliantly won the 2013 tennis grand slam final at Wimbledon, there was uproar in Scotland when he was described in the press as the first “British” player to win Wimbledon since Fred Perry in 1936. (Fred Perry was English).

  Unfortunately you can find examples of this mind-set everywhere. Even in my home city of Aberdeen, this was going on all the time. Although I spent twenty-five years of my life based in Scotland, in my opinion the English have never truly been accepted by the Scots. Your first clue is when you drive north from England on the M6. North of Carlisle, there is a large sign by the motorway saying Welcome to Scotland. The graffiti below this sign reads sorry about the s**t you had to drive through to get here. Nice.

  I do have some limited sympathy for the attitude of the Scots towards the English. For example, the first fast breeder nuclear reactor to be built in the UK was constructed at Dounreay, which is on the very northern tip of the Scottish mainland. This was as far away from London as possible, which baffled the Scots as they were told that this new technology (built to produce plutonium) was one hundred percent safe. So the Scots obviously asked why the government in London did not decide to build this facility in Birmingham or Manchester.

  Another bone of contention came when Margaret Thatcher introduced the community charge, commonly called the poll tax. She imposed her new tax on the Scots first because almost nobody in Scotland voted for her party anyway. After one year of completely ignoring the complaints from the Scots, she imposed the same tax on the English. There was such an outcry that Thatcher had to remove the poll tax legislation completely from the statute books to avoid being thrown out of power.

  Although I do have considerable sympathy for some of the treatment that the Scots have received at the hands of the English, I do think that they tend to go over the top on many occasions.

  I remember the times in my local pub when England was playing in the final stages of the football World Cup, and Scotland had not qualified. All of the flags of the competing nations in the final rounds were suspended from the ceiling of the bar.

  Every time that England was playing, the Scots would hang a large flag of the opposing team beneath the big screen TV. One year when England was finally knocked out by Portugal, the Portuguese flag remained hanging under the TV for a month.

  I have never really understood why they behave in this way. When watching international sports tournaments such as the rugby Six Nations, I will obviously support England as I was born in England. However, if any of the other home nations of Scotland, Wales and Ireland are competing against teams from say France or Italy, I will support the home nations. I think that this underlines the basic difference between the thinking of the Scots from the rest of the UK population.

  I have many friends in Scotland, and I am normally affectionately referred to as English Mike. However when they are inebriated and hunting in a pack, all of the English, including myself, are normally referred to as FEBs (figure it out for yourself). However you learn to live with this, and just let it roll off your back. The Scots are quite polite towards people from nations other than England.

  My wife was from Norway. She, along with other Scandinavian females, were usually just referred to as blue-eyed barracudas, and the males as wooden tops. When it comes to racism, I think that many western governments feel intimidated by non-whites. In the UK everyone calls the British Brits, the Australians Aussies, but if you call Pakistanis Pakis that is racist. Who thought that one up?

  The Scots sometimes go too far though, and they cannot get away with this type of behaviour when they verbally attack the non-European visitors. On one occasion there was a man from Nigeria who was staying in the hotel accommodation above our local bar. One evening he came down to the bar, and insisted that we changed the TV channel even though many locals were in the middle of watching a live sports programme.

  After a heated discussion one of my friends, an elderly Scottish gentleman in his seventies, made a very derogatory racial comment to him, calling him an FBB. The Nigerian gentleman immediately called the police, who dropped what they were doing and had a squad car there within minutes.

  My friend Dougie was promptly arrested, and after removing his belt and shoelaces they held him in a cell at the police HQ overnight. Dougie had his Black Labrador named Beth with him at the time, and I said to him that he should have told the police that he was talking to his dog.

  The Nigerian gentleman in question worked for Shell and was on assignment for several months in Aberdeen. As there were several Shell employees in the bar at the time, this incident got back to the HR department at Shell the following morning. The Nigerian was on a plane back home the next day.

  Now back to the science again. Following the discovery of the electron by J.J. Thomson, the next major step forward in our understanding of physics was made by Max Planck. Planck was a theoretical physicist who developed the theory of quantum mechanics, a cornerstone of modern physics. His work in this field won him the Nobel Prize for Physics in 1918.

  He was born in 1858 in Kiel, Germany. His role as the originator of quantum theory revolutionised human understanding of atomic and subatomic processes, just as Albert Einstein’s theory of relativity revolutionised the understanding of space and time. Together they constitute the fundamental theories of 20th century physics.

  In 1894 Planck investigated the problem of black-body radiation. He had been commissioned by electric companies to create light bulbs emitting maximum light with minimum energy consumption. The problem had been looked at by Kirchhoff in 1859. He investigated how the intensity of the electromagnetic radiation emitted by a black body (a perfect absorber, also known as a cavity radiator) depended on the wavelength of the radiation (i.e. the colour of the light) and the temperature of the body. The question had been explored experimentally, but no theoretical treatment agreed with experimental values.

  Planck’s first proposed solution to the problem in 1899 followed on from what Planck called the “principle of elementary disorder”. This allowed him to derive Wien’s law from a number of assumptions about the entropy of an ideal oscillator, creating what was referred to as the Wien-Planck law. Soon it was found that the experimental evidence did not confirm the new law at all. Planck revised his approach, deriving the first version of his famous 1901 Planck black-body radiation law, which described the experimentally observed black-body spectrum well.

  This first derivation did not include energy quantisation. Planck then revised this first approach, relying on a statistical interpretation of the second law of thermodynamics as a way of gaining a more fundamental understanding of the princ
iples behind his radiation law.

  The central assumption behind his new derivation was the supposition that electromagnetic energy could be emitted only in a quantised form. In other words, the energy could only be a multiple of an elementary unit. This is described by the equation E = h / nu where h is Planck’s constant, also known as Planck’s action quantum (introduced already in 1899), and nu (the Greek letter nu, not the Roman letter v) is the frequency of the radiation.

  Note that the elementary units of energy discussed here are represented by h / nu and not simply by h. Physicists now call these quanta photons, and a photon of frequency nu will have its own specific and unique energy. The total energy at that frequency is then equal to h / nu multiplied by the number of photons at that frequency. For any readers who are students starting to study quantum theory, this is an absolute basic to understand. Today this assumption, although incompatible with classical physics, is regarded as the birth of quantum physics and the greatest intellectual accomplishment of Planck’s career.

  The discovery of Planck’s constant enabled him to define a new universal set of physical units (such as the Planck length and the Planck mass), all based on the fundamental physical constants upon which much of quantum theory is based. In recognition of Planck’s fundamental contribution to a new branch of physics, he was awarded the Nobel Prize in Physics in 1918.

  Subsequently, Planck tried to grasp the meaning of energy quanta, but to no avail. Even several years later, other physicists like Rayleigh, Jeans and Lorentz set Planck’s constant to zero in order to align it with classical physics, but Planck knew full well that this constant had a precise nonzero value.