The word “engineer” derives from its Latin root ingenarius, to mean someone who is ingenious in solving practical problems. Man’s ability to make tools is remarkable. But it is his ingenious ability to make sense of the world and use his tools to make even more sense and even more ingenious tools, that makes him exceptional.
Yet for many, there is a disturbing cloud. Once tools were simple common sense — almost all were understandable to the intelligent layperson. Since the Industrial Revolution, the interior workings of many tools have become mysterious, complex, and opaque to all but specialists. The culture of opposition between the arts, religion, science, and technology has widened and is often antagonistic.
Each of us is struggling for some measure of self-reliance or individual agency in a world where thinking and doing have been systematically separated. We want to feel that our world is intelligible so we can be responsible for it. We feel alienated by impersonal, obscure forces. Some people respond by growing their own food, some by taking up various forms of manual craftwork.
Even when we want to express naked power, we build structures — the old medieval castles with drawbridges are examples. Modern skyscrapers demonstrate the economic power of multinational companies.
So put simply, science is what we know, art is making extraordinary things, engineering is making useful things, technology is applied science, mathematics is a tool and a language, and craft is a special skill.
Then there are whole areas of our lives where science has nothing to offer — it cannot assuage pain or sorrow in times of personal loss — it has no sense of tragedy and no sense of humor. Art, craft, and religion can help to give life meaning and purpose.
The names are reasonably self-explanatory — except for civil. In the 18th century, all non-military engineering was called civil engineering. However, as the need for more specialist engineers developed, so civil engineering has come to refer to construction and infrastructure engineering.
Needing, willing, wanting, desiring, or wishing defines purpose.
The many ways in which we learn to “know” and we learn to “do” evolve in leapfrog fashion. Babies “act” before they “know” — though clearly we are born with inherited genetic innate skills and knowledge by which we learn quickly to grow and develop. But “doing” comes first in the sense that we act before we become aware.
The purpose of science is to know by producing “objects” of theory or “knowledge.” The purpose of mathematics is clear, unambiguous, and precise reasoning. The purpose of engineering and technology is to produce “objects” that are useful physical tools with other qualities such as being safe, affordable, and sustainable. All are activities arising from human will that sustains our sense of purpose. Science is an activity of “knowing,” whereas engineering and technology are activities of “doing” — but both rely on mathematics as a language and a tool.
In STEM, work is defined precisely and objectively so that it is unbiased and independent of personal opinions. Work is the product of force and distance. When we feel energetic, we feel ready to work — so energy is the capacity to do work. Power is the rate of expending energy or doing work.
Their need to feel safe from these other-worldly events drove an activity of creating stories which were the objects that served as explanations or knowledge. Such stories were mythos.
The ideals of mathematical form were divine. The real world was untidy — only the world of forms was perfect (knowledge). It was a dimension of reality that transcended normal experience but was entirely natural.
The pagan Greek attitude had been that manual work was degrading. The Christian religious view was that work was an obligation.
Horseshoes were needed in the wet soils of the north. The stirrup was unknown to the Greeks and Romans. Few inventions have been so simple as the stirrup, but few have had so catalytic influence on history. The stirrup gave the horserider lateral support and revolutionized his ability to fight on horseback.
Before the break this energy is potential — after the break, it had become kinetic. Potential energy is a capacity to do work because of the position of something. Kinetic energy is due to movement. Kinetic energy depends on mass and speed.
So we can see that there are two kinds of work and energy — internal and external. External work is the work done on “something” — it is a demand. Internal work is work done within something — it is a capacity. When all is well, the internal work equals the external work — but both are constantly changing in a process that is successful only if the “something” has the capacity to do the internal work required of it by the external work done on it.
Our understanding and use of heat engines was a long time coming — this was because heat puzzled the ancient thinkers. For example, Aristotle argued that quality and quantity were different categories so he concluded that length was a quantity but heat was a quality.
In 1765, James Watt improved Newcomen’s engine by incorporating a separate condenser and then returning the warm condensed water to the boiler. This meant that the main cylinder didn’t have to be cooled at each stroke but was kept hot throughout — a clear increase in efficiency.
Despite these clear improvements, the early steam engines were still quite inefficient — a better understanding was needed. Sardi Carnot asked himself whether there was a limit to the number of enhancements that could be made to a steam engine.
He was the first to show that no engine could be more efficient than the reversible Carnot cycle. He coined the term entropy to capture the loss of available energy in a heat engine.
A gas turbine jet engine has the same 4 stages as an internal combustion piston engine in your car. It is, however, much more elegant because, rather than happening intermittently, the stages occur continuously and are mounted on a single shaft.
The materials used in the turbine melt at around 1.2K degrees Celsius, so that they have to be cooled. This cooling technology applied to a blade made of ice would keep that blade frozen even in the hottest domestic oven.
In every case, the rigor of engineering and scientific problem solving stemmed from the need to be practical. It required intelligent foresight which includes, but is more than, logical rigor. The whole history of heat engines is not just about finding out new ideas — rather, it is about doing something. The essence of all engineering activity is doing something to fulfill a purpose — a process. It is driven by a strong will to succeed — a will to add value, i.e. to create something of “worth.”
Large-scale power was still not feasible, however, until the permanent magnets were replaced by electromagnets.
AC induction motors are simple, robust, elegant, unglamorous workhorses driving untold numbers of pumps, fans, compressors, hoists, and other modern machinery.
Edison clung to his belief in small-scale DC. He assumed industrial companies would build their own generating plants with his parts. He didn’t see the next step into large power plants and the creation of a national grid to share power.
He set out to replace gaslights with electric ones. He reasoned that electricity was easier to control than gas. Gas sucked oxygen from rooms and gave off toxic fumes, blackened walls and soiled curtains, heated the air, and sometimes caused explosions. Electricity was cleaner and safer.
Combined heat and power (CHP) is the simultaneous generation of heat and power. In its simplest form, a gas turbine, an engine, or a steam turbine drives an alternator and the heat produced is recovered and used to raise steam for industrial processes or to provide hot water. CHP systems make use of the heat produced during electricity generation with overall efficiencies in excess of 70%. This is in contrast with the usual efficiencies of conventional coal-fired and gas-fired power stations, which discard this heat, of typically around 38% and 48% respectively.
At the time when Faraday started his research, electricity and magnetism were conceived as fluids. But his genius and ingenuity, combined with extensive experimentation, led him to an intuitive notion of a field.
Naturally, people have always wanted to send messages. Over 3K years ago, carrier pigeons were used. People have used smoke, fire, beacons, and semaphore. It was therefore completely natural to try to use electricity.
Edison devised a way of sending 2 and then 4 messages down a single cable in 1874. By 1902, a cable was laid across the Pacific Ocean and the world was encircled.
Marconi set about some experiments using a long pole to pick up radiating electromagnetic waves. The long pole became known as an antenna (Italian for pole).
Bell wanted to improve the telegraph, and in doing so invented the telephone. The telegraph was a very limiting way of communicating. Bell wanted to find a better way of transmitting multiple messages over the same wire at the same time. His knowledge of music helped him conceive the idea of an harmonic telegraph whereby several notes of different pitch could be sent at the same time.
FM waves deliver good voice quality, are less susceptible to interference, and are able to carry more information. However, the higher frequencies need a line of sight and so are interrupted by large obstructions such as high hills.
Hollerith spotted the potential for manipulating patterns of information when, in the 1880s, he used punched holes in cards to represent data read by machines. His system saved $5M for the 1890 USA National Census. The machines were eventually electrified and big companies began to input, store, and process more data. Hollerith’s company merged with 3 others to form what was to become IBM in 1924.
By the late 1960s, the average US company was devoting less than 10% of its capital equipment budget to IT; 30 years later, it was 45%; and by 2000, it was the size of all other equipment combined.
They are better than metal wires because they offer higher bandwidth, are lighter in weight, have low transmission loss, are less sensitive to electromagnetic interference, and are made from cheap material. The fibre-optical internet is doing for computing what the AC network did for power distribution because where the equipment is located is not important to the user.
“We must ensure that this never happens again.” How often we hear these words after an inquiry into a failure.
But what is truth? Philosophers have been discussing this issue since Plato. In engineering, as in everyday life, we need a practical commonsense view that helps us to manage acceptable risks. So we accept that a true statement is one that “corresponds with the facts.”
In pre-modern society, there were broadly 2 ways of arriving at truth, mythos and logos. Mythos derived from storytelling. It was often mystical, religious, emotional, and rooted in the subconscious mind. It required faith — belief that cannot be proved to the satisfaction of everyone else — and lacked rational proof. Logos, on the other hand, was rational and pragmatic, and was about facts and external realities — the kind of reasoning we use to get something done.
The job of the engineer is to make the risks acceptably small. In doing so, engineers do not look for truth — that is the purpose of science — rather, they look for reliable, dependable information on which to build and test their models of understanding. They are acutely aware of context.
Indeed, if you prick a balloon before you blow it up, it will leak not burst.