This section aims to convey to the Engineering student what the profession is in a descriptive way, so that the functions that a practicing engineer fulfills are understood. To do this, we will start with what Engineering has historically been.

The origin of engineering

Engineering appeared with the first human being. Engineering can be spoken of from the first moment a stone was shaped into a tool, or when the first humans used energy consciously by lighting a fire. Since then, the development of Engineering has gone hand in hand with that of Humanity.

The origins of many of the techniques and tools in common use today are lost in antiquity. Perhaps the most obvious example is the fact that almost all modern methods of power generation are based on fire, of which no one knows when it was first achieved, but it clearly required significant brainpower. Other examples can be cited of essential elements for the current development of technology, such as the wheel, the lever, the pulley and the methods for casting metals, which have been used for thousands of years and which it is not possible to set date

Stone work was highly developed in ancient times, as evidenced by the gigantic structures of Mesopotamia, Egypt and Central America that still exist today. Thus, for example, the largest of the pyramids, the Great Pyramid of Cheops originally had a height similar to that of a 48-story building and its construction can be set between 4235 and 2450 BC. It is a monument to the capabilities of people that has stood the test of 6,000 years.

There were other achievements in Antiquity, perhaps not as spectacular as the pyramids but with a greater impact on the development of Humanity, such as the construction of canals and aqueducts, which made possible the appearance of cities and the expansion of agriculture. Long before 3,000 BC, the Sumerians had drained the marshes of the Persian Gulf and built canals for irrigation. In the same way, the substitution of human energy for other types of energy, or the development of these new sources have also been fundamental milestones in the development of the technique. The use of oxen and later with the appearance of the plow, of horses (faster and more efficient than oxen), allowed man to have new sources of power. In this sense, the most important leap was made when animal energy was replaced by mechanical energy, beginning the period known as the Industrial Revolution.

Special mention should be made of the developments achieved in Ancient China. One of them has already been mentioned, the plow, but there were many and of great importance the developments imported by the West, such as paper (remember that the degree of development of a society is measured by the amount of paper consumed), the crankshaft, which allows linear movements to be converted into rotary movements and vice versa, or gunpowder. Also in the West contributions of vital interest were made. The Romans invented mortar and spread an element whose capacity provided unknown possibilities: the arch. However, its inventors, the Etruscans, made little use of it. The arch made it possible to build the spectacular European Gothic cathedrals, long before the development of any theory of structures.

The Middle Ages are normally thought of as a period of stagnation characterized by a lack of social progress. However, some of the greatest architectural creations of Humanity, the cathedrals, date from that time. Furthermore, two machines invented in that period have had a huge impact on subsequent progress: the counterweight clock and the printing press, invented by Gutenberg in 1450. Georgius Agricola (1494-1555) and Galileo Galilei (1564-1642) established the scientific foundations of engineering. The first, in his posthumous work De Re Metallica (1556), systematically compiled and organized all existing knowledge on mining and metallurgy, being the leading authority on the subject for nearly 200 years. Galileo is known for his astronomical observations and for his statement that objects of different masses are subjected to the same "rate" of fall. Galileo also tried to develop tensional theories for structures. Although his predictions were wrong by not considering the elasticity of materials, shortly after Robert Hooke published the first article on elasticity (1678) that laid the foundations for the current theory of elasticity. As can be seen, geniuses appear in history whose influence on the subsequent development of the technique is enormous. Galileo was one of them, as was Newton, whose main legacies were the three famous laws of motion, the solution to the problem of the movement of the planets, and the development of mathematical calculation.

The 17th century was, as can be seen, exceptional for the further development of engineering. Towards its end, a crucial event occurred, since man learned to convert heat energy and