Seven Elements That Have Changed the World (49 page)

37.
This is the Shard, which opened in July 2012 with a laser show across London.

38.
The Music Lesson
, Hiroshi Sugimoto (1999), author’s collection.

39.
Jonathan Miller,
On Reflection
:
An Investigation of Artists’ Use of Reflection Throughout the History of Art
(New Haven: Yale University Press, 1998), p. 124.

40.
Republic
(X, 596) in Melchior-Bonnet,
The Mirror
, p. 104.

41.
Glass lenses, named for their resemblance to lentils or, in Latin, ‘lenses’, had been sold by spectacle makers since the middle of the fourteenth century, but the telescope was not invented until over a century later. In October 1608 the General Estates of The Hague received a petition from Hans Lippershey for a patent to build an instrument for ‘seeing faraway things as though nearby’. Patent Application of Hans Lippershey, 2 October 1608. The Hague, Algemeen Rijksarchief, MSS ‘Staten-Generaal’, Vol. 33. F. 178v.

42.
Michael Hoskin,
The Cambridge Concise History of Astronomy
(Cambridge: Cambridge University Press, 1999) p. 112.

43.
Nicolaus Copernicus,
De revolutionibus
, 1543. Along with Galileo’s observations, the accurate observations of Tycho Brahe, who set new standards for astronomy in the sixteenth century, and the new laws of planetary motion formulated by Johann Kepler, were crucial in formulating a plausible account of a Sun-centred model of the Universe.

44.
Galileo’s Principle of Inertia provided an explanation for this ‘problem’. According to his principle, a body moving at a constant speed will continue moving at that speed unless it is disturbed. As the Earth, and everything on it, moves at a constant speed, no force is felt.

45.
Hoskin,
The Cambridge Concise History of Astronomy
, p. 112.

46.
Glass bends or ‘refracts’ different colours of light by a different amount. This is why Newton’s glass prism produced a rainbow. For an image to be produced close to the lens, the light must be sharply refracted using a more curved, and so thicker, lens. But this lens will also increase the discrepancy in refraction between different colours of light, so that a blurred image is produced. Using a thinner, more gently curved lens produced a clearer image, but the much longer focal length meant that a much longer telescope tube was needed.

47.
Herschel understood that telescopes collect light ‘in proportion to their apertures, so that one with double the aperture will penetrate into space to double the distance of the other’. The brightness of a star decreases rapidly with its distance from Earth, and so a mirror which collects more light can see stars which are further away. Pendergrast,
Mirror
,
Mirror
, location 2024/5102.

48.
Pendergrast,
Mirror
,
Mirror
, location 2024/5102.

49.
Many of Herschel’s telescopes were not made from silvered glass, but from speculum metal, a brittle and hard casting composed mainly of copper and tin.

50.
The Great Art of Light and Shadow
(1646), in Frank Kryza,
The Power of Light
(New York: McGraw-Hill, 2003), p. 36.

51.
Many historians believe that it really is no more than a legend. Experiments have even been carried out to replicate the event; even with the intense Sicilian sun, the army’s bronze reflectors would probably have resulted in little more than smoking and charring of the enemy’s wooden ships.

52.
He used the same mirror to melt gold ducats. Biringuccio,
Pirotechnia
, p. 387.

53.
Leonardo’s design used a mosaic of silvered glass pieces stuck to the bottom of the curved basin. In a note he wrote: ‘With [this device] one can supply heat to any boiler in a dyeing factory. And with this a pool can be warmed up, because there will always be boiling water.’ Kryza,
The Power of Light
, p. 57. See also the image from Leonardo’s notebook reproduced in this volume.

54.
Bessemer’s son, in Bessemer,
An Autobiography
, p. 36.

55.
Shuman’s hot box trapped heat in the same way as greenhouses do. Glass traps heat because it is transparent to electromagnetic radiation of optical wavelengths (visible light) which is emitted from the sun with a high intensity, but it is opaque to electromagnetic radiation of longer wavelengths, such as the infrared radiation that is dominantly emitted from the ground. Light enters in through the glass and is absorbed by the ground. When the energy is re-emitted as infrared radiation, it cannot pass through the glass and so the heat becomes trapped.

56.
Kryza,
The Power of Light
, p. 11.

57.
A. E. Becquerel, ‘Mémoire sur les effets électriques produits sous l’influence des rayons solaires’,
Comptes Rendus
, 9, pp. 561–7 (1839).

58.
Pearson and Fuller’s work at Bell Labs was not originally aimed at creating a
photovoltaic device; instead they were attempting to produce a better silicon transistor.

59.
Yergin,
The Quest
, p. 570.

60.
Silicon has four electrons in its outer shell, like carbon, and so bonds together to form crystals, in the same way that carbon atoms bond to form diamonds. To knock an electron out of this crystal structure requires a lot of energy and so, as an electrical current consists of flowing electrons, pure silicon at best can carry an extremely small current. A better semiconductor can be created by ‘doping’ the crystal with atoms of other elements. Either these atoms add extra electrons to the crystal, or they act as a ‘hole’ into which electrons can fall, so that a larger current can flow. If the semiconductor has an excess of electrons it is called an N-type (N for negative) semiconductor; if it has an excess of holes it is called a P-type (P for positive) semiconductor. A solar cell is made from a layer of N-type silicon sandwiched with a layer of P-type silicon. An electric field is created across the two layers between the negative free electrons and positive free holes. When a photon is absorbed by the solar cell it breaks apart an electron-hole pair into a free electron and a free hole, which are then swept to opposite sides of the device by the electric field. This flowing current can be harnessed as electrical power.

61.
Silicon is an important tool on both the renewable and non-renewable sides of the transition. Shale gas is released from rock formations by the injection of sand (silicon dioxide) and water at high pressure.

62.
‘Vast Power of the Sun Is Tapped By Battery Using Sand Ingredient’,
New York Times
, 26 April 1954.

63.
IBM 11230, Initial Press Release, IBM Data Processing Division, 11 February 1965.

64.
In 2002, an unprecedented survey was carried out over the
Thunder Horse
field, producing around 28 terabytes of data, a billion times greater than the memory of the IBM 1130. It took BP’s High Performance Computing Center in Houston about a month to process this data; but only two years earlier the same job would have taken almost two years, too long to be of value for the project.

65.
Inside vacuum tubes hot filaments emit electrons that are then subsequently attracted to a positive voltage plate. As the plate is cold, and so does not emit electrons, the current flows in only one direction. If a negative voltage plate is placed between the filament and the positive plate, electrons are deflected away and current does not flow. Turn this plate off and current will flow as before. By turning the central negative plate on and off the vacuum tube can be used as a switch. The vacuum tube will also act to amplify the electrical signal put into the central negative plate.

66.
Shockley’s interest in semiconductors began during the Second World War, when he developed technology for the detection of radio waves. During the war, Shockley also influenced the decision to drop an atomic bomb on Hiroshima and Nagasaki
when he helped to produce a report on the probable casualties if Japan was invaded.

67.
Bardeen and Brattain used a conducting fluid to create an electric field at the surface that broke down the surface state and so enabled current to flow.

68.
The name of the transistor comes from ‘transfer resistor’. Soon after the invention, co-worker John Pierce was walking by Brattain’s office and was called in. Asked about a possible name for the device he recalled: ‘I thought right there at the time, if not, within hours, I thought vacuum tubes have trans
conductance
, transistors would have trans
resistance.
’ There were resistors and inductors and other solid states, capacitors and
tors
seemed to occur in all sorts of electronic devices. From transresistance I coined
transistors.
’ Shurkin,
Broken Genius
[ebook], location 1889/5785.

69.
Transistors are made from a stack of three semiconductor layers, either NPN or PNP (see note 60, above, for an explanation of doped semiconductor layers). The bottom layer acts as a source of charge carriers, the top layer acts as a drain of charge carriers and the middle layer acts as a channel through which charge carriers can (sometimes) flow. When the source and drain are attached to a battery, current cannot flow through the semiconductor layers. For example, in a PNP transistor, electrons will only flow from the negative battery terminal into the P-type semiconductor; both the positive battery terminal and the other P-type semiconductor that join the circuit are positively charged and so the charges will repel and no current will flow.
     If, however, you inject some electrons into the middle layer of the sandwich through a ‘gate’, the electrons will move into the P-type semiconductor and a small current will flow. This small current acts as a switch that allows a much larger current to flow through the channel amplifying the original signal. In this way transistors act as both a switch and an amplifier.

70.
Fortune
, March 1953, p. 129, in Joel Shurkin,
Broken Genius
(London: Macmillan, 2006), p. 120.

71.
At the time germanium was more readily available at the necessary purity than silicon. The first silicon transistor was not invented until 1954, but soon proved its worth. Silicon transistors work at high temperatures, vital for the military applications in which the first semiconductor devices were used.

72.
Fortune
, March 1953, p. 128.

73.
Shockley wrote: ‘I experienced some frustration that my personal efforts, started more than eight years before, had not resulted in a significant inventive contribution of my own.’ Driven by his anger at not having followed through his transistor idea, Shockley set about designing a new and better type of transistor. He accomplished this a few months later. The ‘junction transistor’ is the forerunner of virtually all transistors used today. Shurkin,
Broken Genius
, pp. 107–8.

74.
Christophe Lecuyer,
Making Silicon Valley
:
Innovation and Growth of High Tech
,
1930–1970
(Cambridge, MA: MIT Press, 2006), p. 133.

75.
In computer factories, hundreds of lab coat-clad women would attach individual wires by hand to the join the devices.

76.
Fairchild had a problem with the fragility of their silicon transistors: it would take little more than a sharp pencil tap against their transistors to stop them working. Jean Hoerni solved the problem when he discovered that the oxide layer usually washed off the semiconductor would actually protect its surface. He proved the invention to his co-workers by spitting on the surface.

77.
Leslie Berlin,
The Man Behind the Microchip
(Oxford: Oxford University Press, 2005), p. 108.

78.
At first no one knew how to do this and many saw little potential in the idea; it required such a step change in production that the first integrated circuits would be very expensive. Only the military would pay a premium for small improvements in weight and reliability. Yet Noyce saw the potential for his idea to revolutionise the computing industry and continued to support research into the development of the integrated chip at Fairchild. Gradually the importance of the idea became apparent. Noyce regarded his invention as a breakthrough in a process problem, rather than the discovery of any new science. Whenever asked when we would get his Nobel Prize for his achievement he always responded sardonically, ‘They don’t give Nobel Prizes for engineering or real work.’ That situation I hope will change soon with the recent creation of the Queen Elizabeth Prize for Engineering, of which I am chairman. Noyce was never awarded a Nobel Prize, but would undoubtedly have shared the Prize given to Jack Kilby had he still been alive in 2000.www.qeprize.org. Berlin,
The Man Behind the Microchip
, p. 110.
     Today integrated chips are produced by a method called photolithography. A thin silicon wafer is covered with a layer of insulating silicon dioxide and, on top of this, a layer of protective photosensitive material. When UV light is shone on to this material, the protective layer breaks apart and can be washed away. A mask is used so that the UV light only reaches parts of the chip where the circuit components are to be printed. After the protective layer has been washed away, chemicals are used to etch away the silicon dioxide in the same areas, revealing the silicon wafer beneath. The electrical properties of the silicon can now be altered as a first step to producing a transistor. For example, the silicon might be doped by adding other atoms of other elements to form one layer of a NPN or PNP junction (see note 60, above). This process is repeated to simultaneously build up all the components of the circuit. When all the components of the chip have been formed, a thin layer of metal is added over the top. The metal layer is then etched away so that the components are connected as desired. This is done using another photosensitive layer and another mask, this time in the shape of the connecting ‘wires’. Complex circuits require many layers of components and metal ‘wires’.