Engineering has been considered as the practical application of science for over two centuries. ABET, Inc., formerly the Accreditation Board of Engineering and Technology (www.abet.org), the organization that evaluates and accredits college and university programs in applied science, computing, engineering, and technology in the United States and many other countries, defines engineering as follows:
Engineering is the profession in which a knowledge of mathematical and natural sciences, gained by study, experience and practice, is applied with judgment to develop ways to utilize economically the materials and forces of nature for the benefit of mankind.
This is an all-encompassing definition that makes it clear that engineering is based on science and harnesses resources for the benefit of mankind. Any activity practiced today as engineering would certainly be covered by this definition, and yet, the definition suffers from the disadvantage of being too general. Practically any commercial venture can be construed as an engineering activity according to this definition. Further, this definition does not help distinguish between science and engineering. Landis [4] has compiled 21 different definitions of engineering by various individuals over the last two centuries, and the recurring theme in these definitions is that engineering is the application of science for the benefit of humanity. As with the ABET definition, any engineering activity practiced today would conform to any one of these definitions, and yet, the definition would not be exclusive to engineering activities.
Obviously, defining engineering is not an easy task (we would have already had a more than adequate definition if it were so), and it would be better to describe characteristic attributes of engineering before attempting to develop a new definition for it:
• An engineering activity has an economic impact associated with it: An organization engages in engineering activity in order to derive immediate commercial or other benefit from it. The commercial benefit is primarily through generating revenue and profit through the manufacture of products, provision of service, supply of energy, and so on. The commercial benefit may also take the form of cost-aversion, such as avoiding penalties and taxes through the treatment of waste streams prior to releasing them in the environment. Certain engineering activities, particularly those conducted by governmental or quasi-governmental entities, may not have immediate or direct commercial benefit. For example, public works such as bridges, roads and dams, or weapons development and other military engineering activities may not generate revenue/profits but have implicit economic value to the society and the nation. These activities build infrastructure that makes economic growth possible and protect the people from external dangers that, among other impacts, threaten the economy of the nation. Similarly, engineering clean-up of polluted waterways and air and soils also has positive economic impact on the society through aversion of healthcare spending and other costs and increasing the resource availability for economic activities.
• An engineering activity is conducted for the benefit of society at large: Engineering activities are undertaken to satisfy the demand for products, services, and energy by the society. In other words, the public at large is the direct beneficiary of engineering activities, be those in the form of power plants, automobiles, machines, or clean environment. Some of these activities, particularly public works activities, benefit each and every member of the society. Other activities that are purely commercial in nature are targeted at the customers of the products and services of such activities. For example, an automobile manufacturer produces cars to satisfy the market demand for them. The customer for the product is any member of the society, any individual who has the need and resources to afford the product. This aspect of engineering activities contrasts with scientific activities, which while adding to our knowledge, are of direct benefit only to a more specialized group of people, namely other scientists, engineers, and technical professionals in that specific field.
• Engineering involves application of scientific knowledge: As the ABET definition states, engineering utilizes science for practical purposes. Science is essentially a field of discovery where fundamental understanding of processes and phenomena is the objective. Scientists seek to produce knowledge that enables us to explain observed phenomena and elucidate underlying laws of nature. Engineers apply this knowledge to create products, processes, and services to improve the quality of life of people. A scientist is typically driven by the desire to derive a global understanding of the phenomena; in other words, the knowledge is not complete until each and every factor affecting the phenomena is identified and a theoretical explanation proposed and validated for every observed effect. Such knowledge is obviously beneficial to the engineer; however, an engineering activity can proceed without necessarily having the complete theoretical scientific understanding and framework for the process. As it is often said, the steam engine was developed before the science (thermodynamics) behind it was fully understood.
• Engineering activities are conducted on a large scale: A key significant characteristic that distinguishes engineering from science is the scale of activities. Science involves discovery of new products, principles, and processes in a laboratory or research setting. Engineering involves taking this novel discovery and scaling up to make it accessible and affordable to the entire society. A chemist may synthesize a new chemical with promising properties in the laboratory in milligram quantities, starting with high-purity substances. An engineer develops, on the basis of the reaction discovered in the laboratory, a commercial process producing the same chemical in bulk quantities (kilograms or tons, a scale-up factor of a million or more) starting with the cheapest substances possible. Scientists discovered radioactivity and nuclear fission; engineers utilized this knowledge to build nuclear power plants for electricity generation. The key challenge in engineering is to ensure that the outputs of industrial commercial ventures have the same properties (including purity) and functionality as the laboratory products while minimizing the energy and resource consumptions, and realizing economic benefit.
It should be noted that scale can refer to either the size or the number of the products of the engineering activity. Figure 1.1 shows the massive Hoover Dam on the Colorado River in the United States, a structure that required more than 5 million barrels of cement. Weighing in excess of 6.6 million tons, the Hoover Dam was the largest dam of its time when completed (www.usbr.gov/lc/hooverdam/faqs/damfaqs.html).
Figure 1.1 The Hoover Dam on Colorado River.
Source: Photo courtesy of the U.S. Bureau of Reclamation, www.usbr.gov/lc/hooverdam/images/D001a.jpg.
Not every product of engineering activities has such large dimensions. Figure 1.2(a) shows a 300-mm diameter silicon wafer containing a large number of microchips, each containing an integrated circuit similar to one shown in Figure 1.2(b) with the interconnections having a width of only a few nanometers [5]. Figures 1.1 and 1.2 both show manifestations of remarkable engineering endeavors.
Figure 1.2 A silicon wafer with microchips—(a) wafer, (b) a single microchip.
Source: Shackelford, J. F., Introduction to Materials Science for Engineers, Seventh Edition, Prentice Hall, Upper Saddle River, New Jersey, 2009.
These characteristics point out engineering as the activity that makes science a reality for the common man. It transforms the knowledge from the realm of a select few to an entity that can serve a consumer for betterment of the quality of life. The basic laws of mathematics, physics, and chemistry are harnessed through engineering to manufacture automobiles, planes, and other machines; build dams, highways, and other structures; construct power plants to supply electricity and refineries to provide gasoline; and countless such endeavors. A consumer, the beneficiary of these undertakings, does not need to have even a rudimentary understanding of the fundamental scientific laws to enjoy the resultant product or service, thanks to engineering.
An alternative way of expressing the same idea is to say that engineering is the process of transforming science into technology. This definition introduces an additional concept—that of technology. Technology is variously defined as (1) the application of science for practical purposes, (2) a branch of knowledge dealing with engineering or applied science as a machine, and (3) a piece of equipment developed from scientific knowledge. The first definition makes technology virtually indistinguishable from engineering, and the second definition lacks clarity. The third definition is the closest to the meaning intended in this book, as elaborated in the discussion that follows.
Science comprises the natural laws that govern the behavior and interaction of inanimate and animate objects. Technology is the manifestation or implementation of this knowledge in the form of a manufacturing, treatment, or other process that yields a machine, an object, or a service that is used by a consumer. For example, an automobile is the product of a manufacturing technology developed on the basis of laws of physics. Similarly, principles of chemistry are harnessed in another type of manufacturing technology to obtain a chemical product, such as sulfuric acid.
Not all technologies yield tangible objects such as sulfuric acid or an automobile as their end products. The products of information technology, based on mathematics and computer science, are frequently services in the form of software packages and programs used by consumers. Technology is essentially science-based process (or technique) that yields an object or a service that is used by the consumer, who need not have any understanding of the fundamental scientific principles on which it is based.
Once science is understood to be the foundation of the structure that is technology, engineering can be easily understood as the process of developing and building the structure. Engineering thus differs from both science and technology in being an action rather than a concept or an object. The initial starting point of engineering activities is science, and the end result is technology. Science and technology can be viewed as the initial and final states, and engineering, the process of traversing the path between them. Engineering also includes the actions that result in improvement of technology. This dynamic nature of engineering distinguishes it from both science and technology.
With this concept of engineering, an engineer can be conveniently defined as an individual engaged in the practice of engineering. An engineer must possess the scientific knowledge, but the overarching goal of the engineer is to apply this knowledge to create useful things—technology—for everyone. Discovering new knowledge is not an engineer’s principal function, although some engineers may indeed add to the knowledge base while devising practical applications of science.
This scheme of things also allows us to define the role of a technologist with greater clarity. A technologist is the individual who has the responsibility to operate and ensure that the technology functions as designed and intended.2 The technologist must understand how the technology operates; however, a technologist is not required to know how the technology was developed. A technologist may use his/her experience and empirical knowledge to effect improvements in the technology, but those activities would not qualify as engineering activities in the rigorous sense of engineering.
2. Despite the nature of responsibilities, these positions are most often termed as engineering positions.
In the past, it was possible for an individual to acquire the necessary knowledge to practice the engineering profession through experience; however, at the present time a degree from an ABET-accredited program is indispensable for one to be qualified and licensed as a professional engineer.3 These engineering programs feature rigorous science, engineering science, and engineering courses to prepare the individual for an engineering career.
3. Each state in the United States has its own board of licensed engineers that administers the necessary examinations to certify an individual as a professional engineer who can then legally engage in engineering practice.
Many universities also offer degree programs in engineering technology that prepare individuals for a career as a technologist. These programs are typically characterized by lower mathematical and scientific rigor and absence of the design component as compared to the engineering programs [3]. The emphasis is on understanding the operation of the process and maintenance of machinery. The actual operation of the machinery and the process is done by technicians skilled in the particular trade. The technical skills and knowledge necessary for such duty are typically acquired in a vocational school that offers an associate’s degree or a certificate course or are learned on the job. The associate’s degree or certificate programs are of shorter duration and feature less rigorous science and mathematics courses.
Based on the nature of engineering practice, the engineering field is divided into several disciplines. These disciplines are described briefly in the next section.
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