In the last six decades, computers have developed faster speeds, larger memory storage, and smaller footprints. The smart phone many people carry in their pockets today has more power, speed, and storage capacity than the early computers, which were hampered by reliance on large vacuum tubes. These tubes were exceptional technology during their time, but they had many disadvantages — they required time to “warm up,” they produced a great deal of heat, and they were easily broken. Most of all they were large, and as a result, the computers containing them could be as big as one entire floor of a large building.
One of the first breakthroughs which helped computers become faster and smaller was a product of materials science. The three essential properties of a material are 1) the atoms of which it is made; 2) the way in which those atoms are bonded; and 3) the arrangement of atoms in the material. For example, glass is 1) primarily composed of silicon, oxygen, sodium, carbon, and calcium, in the form of SiO2, Na2O, CaO, and Na2CO3; 2) which are bonded covalently (atoms share electrons); and 3) form an amorphous (non-crystalline) solid. On the other hand, lodestone is 1) composed of iron and oxygen; 2) bonded ionically; 3) which forms a crystal structure of 3 iron atoms to 4 oxygen atoms.
Semiconductors are exactly what they sound like: substances that act in a manner in between a conductor and an insulator. They may be elemental, i.e., composed of a single element such as silicon or germanium, or compound, i.e., composed of two elements such as gallium and arsenic. The properties of semiconductors are based on their bonding, which involves sharing of electrons. This is a type of covalent bond, but it is different from other covalent bonds due to the arrangement of electrons in their orbitals around the atomic nucleus (David, 2005).
The elements carbon, silicon, and germanium are aligned in the periodic table, and they each have four electrons in the outer orbital. The four electrons repel each other, forming a tetrahedral shape. They bond covalently, forming a lattice consisting of electrons and holes. The electrons and holes move, providing the desired level of conduction. Natural semiconductors are also called intrinsic and have equal numbers of electrons and holes; therefore their ability to conduct is very low. An extrinsic semiconductor material is a modified intrinsic one, with impurities added (called doping) to control its ability to conduct. Extrinsic semiconductors can primarily conduct negative or positive charges, depending on the impurity added (Chatha, 2014).
A transistor is made of semiconducting material (often silicon-based) and its importance in the electronic equipment of today cannot be overestimated. Without the transistor, desktop computers and all other electronics would be impossible. An essential element of transistors is that they can emit power greater than what is input; they are amplifiers. Transistors can be used to provide an interface between low current and high current devices, to switch on another part of a circuit, and as electronic switches within a single circuit (BBC, 2014). The type of transistor termed the “point-contact” transistor was developed at Bell Labs during the 1940s. Three researchers, Shockley, Bardeen, and Brattain, were awarded the Nobel Prize in Physics of 1956 for this work (Nobel Media, 2014).
The development of microchips further miniaturized the circuits needed for a computer, allowing them to become even smaller. A microchip is a small piece of semiconductor material (usually silicon-based) that has undergone a process that is called photolithography. This process uses light and chemicals to imprint a pattern on the chip, producing an integrated circuit, so called because the complete circuit is present on a single chip (integrated). However, integrated circuits can also be produced on other materials such as thin or thick film, as well as in hybrid circuits, which contain separate components along with printed circuits molded together and attached to a circuit board (Nobel Media, 2013).
The field of artificial intelligence is the scientific investigation of intelligent machines / computer programs. A.I. is sometimes used to explore the capabilities and limits of human and animal intelligence, along with processes that control development of the human mind. For example, machine learning was once considered impossible, but it is a reality today. Programs for speech recognition are able to adjust to an individual’s particular speech sounds. Knowledge discovery and data mining (KDD) involves using the most intelligent computers to process large data sets and note patterns — such as data from the SETI (Search for Extra-Terrestrial Intelligence) project.
Defining intelligence is difficult, even though most people believe they can recognize intelligence when they encounter it. This idea is the basis of the Turing test, proposed by Alan Turing in the mid-20th century. In this test, a human would interface with a computer by text messages. Sometimes a real human being would respond, and other times the machine would respond. For a machine to pass the Turing test, its responses would be so similar to the human’s responses that the other person could not tell which was which. Although some attempts have appeared to pass, they may have pointed out the need for an intelligent, educated person to make the determination (McCarthy, 2007). Dylan Love of Business Insider looks into the world of communications between ‘artificially intelligent’ chatbots and finds it awkward and weird.
These results are not surprising because computers and human brains are quite different. First, the brain is composed of neurons which, because of multiple ways they can connect and communicate, are much more data rich than components of a computer. Second, the brain has one problem solved at an unconscious level: perception. Computers are notoriously inefficient at taking in “sensory” data and making “sense” of it. The consciousness of the human brain is able to focus on more demanding mental tasks because the work of perception is taking place unconsciously.
- BBC. (2014). GCSE Bitesize: Switches, transistors, and relays. Retrieved from http://www.bbc.co.uk/schools/gcsebitesize/design/electronics/switchesrev3.shtml.
Chatha, K. (2014). Semiconductor basics. Retrieved from http://enpub.fulton.asu.edu/widebandgap/NewPages/SCbasics.html
- David, E. (2005). Notes for Microelectronics Fabrication I. Retrieved from http://web.pdx.edu/~davide/notes.pdf.
- Love, D. (2014). It gets pretty weird when you have two ‘artificially intelligent’ chatbots talk to each other. Business Insider. Retrieved from http://www.businessinsider.com/artificial-intelligence-chatbots-and-the-turing-test-2014-5.
- McCarthy, J. (2007). Artificial Intelligence Basics. Retrieved from http://www-formal.stanford.edu/jmc/whatisai/node1.html.
- Nobel Media. (2013). The Integrated Circuit. Retrieved from http://www.nobelprize.org/educational/physics/integrated_circuit/
- Nobel Media. (2014). The History of the Transistor. Retrieved from http://www.nobelprize.org/educational/physics/transistor/history/