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3.2: To Engineer Is Human

Difficulty Level: At Grade Created by: CK-12

The ancient pyramids are an engineering marvel. The great pyramid was the tallest man-made structure in the world for almost four thousand years.

Engineering is a human endeavor. Humans have engaged in engineering to meet their needs as long as they have had needs. We invent and innovate when we are confronted with problems, needs, and desires. Inventions exist and continue to be created to meet our needs for daily life, such as access to water, energy, transportation, and entertainment. Petroski (2004) said, “Making things is an activity as old as civilization, and making ever new things is part of being human.” Our lives are permeated with technological inventions that humans have engineered (Figure 1). Yet, the fundamental nature of engineering or what engineers do is not everyday knowledge. For instance, many of us are unfamiliar with the basic principles used to build the systems that deliver water, gas, or electricity to our homes.

Engineering is the design, analysis, and creation of things that are practical and useful in our lives. At its core, engineering incorporates design. Design, simply put, is creating something that has not existed before. Engineers help design, create or change almost everything we encounter in our lives, including what we feel, eat, see, and hear.

In this section, we consider several different engineering achievements that have dramatically changed the way we live today. We then consider the impact of engineering on sustainability of natural resources, and focused briefly on one very important resource: water.

Human Needs Are Met By Engineering

To stay alive, humans and animals need only the basics of water, food, and shelter. In addition to these basics, animals, and at times humans, too, need protection from other animals that are predators. For the most part, however, humans today do not have to worry about becoming food for other animals. Although we need water, food, clothes, and shelter, not very many of us fetch water from a well or a river; grow or kill our own food; make our own fabric and sew clothes; or, build our own homes with our own hands. We do not do this on our own because people have invented products, tools and systems to do it for us, allowing us to spend productive time in other ways.

We prefer to do something other than figure out how to get clean water to our homes, grow crops, raise poultry, make fabric and sew clothes, or construct homes. This is possible because of all the people before us who created inventions that met their and our needs. These inventions range from the basic technology of the plow or the wheel to today’s advanced technologies that allow us to manage and sustain our natural resources or engage in space exploration. Human needs and wants have been met throughout time by engineering achievements that have significantly transformed and impacted our lives, especially over the past one hundred years.

The National Academy of Engineering (NAE) has identified the top twenty engineering achievements of the twentieth century; these achievements are documented in the book by Constable and Somerville (2003) and on the webpage (http://www.greatachievements.org/). These achievements are described in more detail in the chapter Nature of Engineering. These achievements include many of the technologies that we use every day and may take for granted.

One of these achievements that we will consider in more detail in this chapter is water supply and distribution. Water is vital for our lives. When we turn on our kitchen faucet and clean drinking water flows from the faucet, we seldom pause to think how that water got there (Figure 2). However, delivering clean water to your home or school or office requires an advanced system of treatment and distribution facilities. Imagine your life without indoor plumbing. Yet, even in today’s world, there are many who live without access to running water, toilets, bathtubs, or showers. Maintaining water quality and distributing water to people where they live are timeless challenges. It is important to remember that water is not merely needed for our basic survival; in today’s world water is used for many other purposes that sustain our way of life.

Most people in the United States are fortunate to have safe drinking water.

Engineering Sustainability for Our Future

Current projections predict that the earth’s human population will be around 9 billion in 2050. By the year 3000 the world’s population is predicted to be double that of today’s 6.6 billion. Most of this expected increase is predicted to be concentrated in the developing nations of Africa, Asia, and Latin America. Meeting the most basic needs of this future population means an ever-growing stress on our environment and limited natural resources. This means increased production and consumption of goods and services and increased demand for land, energy, and materials (NRC, 1999). While the engineering achievements of the past century have increased the standard of living in developed countries, the challenge of the future is to alleviate poverty and raise the standard of living for all on this planet while also sustaining our natural resources.

As we consider the engineering achievements of the past, we also need to consider their unintended consequences on our lives and our planet. We must ask ourselves: What are the social, economic, and environmental impacts of our engineering achievements? Many engineering decisions cannot be made without consideration of nearby natural and man-made systems, because contemporary engineering systems can affect the environment far into the future. There is a strong need to reduce the risk and level of unwanted disturbances to natural resources and our man-made world associated with engineering systems.

According to the National Resource Council (NRC, 1999): “Sustainable development—the reconciliation of society’s developmental goals with its environmental limits over the long term—is the most recent conceptual focus linking the collective aspirations of the world’s peoples for peace, freedom, improved living conditions, and a healthy environment.” Engineers have an obligation to meet the basic needs of all humans for water, nutrition, energy, sanitation, and health, as well as the protection of the planet’s resources, including our cultural and natural diversity.


Water covers 71% of the Earth's surface. This photograph of Earth's polar ice and oceans was taken by the Galileo space probe.

The next section focuses on one of the basic human needs: water. Water is a common substance. Its chemical formula of \begin{align*}H_2O\end{align*}H2O is widely known. It is a life-giving natural resource. Seventy-one percent of the earth’s surface is covered in water, most of which is salt water (Figure 3). Water is essential to most organisms on Earth. For instance, \begin{align*}50-70\end{align*}5070% of a human body is made up of water.

Water is one of the few substances on the planet Earth that can be found occurring naturally in all three states: solid (ice), liquid (water), and gas (water vapor). A significant difference between these states is the density of each state. (Density here refers to how close the water molecules are to each other. The mass of water within a specific volume determines the density of water.) The vapor state is least dense, while the liquid state is most dense; the solid-state (ice) is less dense than the liquid state. Warm water is less dense than cold water. Therefore, heating and cooling water affects its density.

Water is a very good solvent for many compounds. Therefore, almost no pure water exists in nature; most water contains dissolved substances. After water falls to earth in the form of precipitation, it dissolves substances from soil and rocks. This leads, for example, to hard water, which is water that has magnesium and calcium dissolved in it. Next time you buy bottled water, read the label. You may discover, to your surprise, that your pure spring water is not merely \begin{align*}H_2O\end{align*}H2O, but also contains chemicals. In fact, the label on your bottled water may even list the chemicals and their amounts. Most water you drink has ions in it. Those ions in the water make it acidic or basic. The \begin{align*}pH\end{align*}pH of water is a measure of its acidity or alkalinity; The \begin{align*}pH\end{align*}pH index is related to the amount of free hydrogen ions in the water.

Water is a natural resource and sustaining it for future populations is a major challenge that will require creative engineering. Water is used by industry, agriculture, and homes. In many places in North America, people have access to all of the clean water they need. However, there are many places in the world where water supply is limited. Most uses of water actually decrease the quality of the water; this is true of water that is used in many industrial processes as well as water used by humans.

Our family, our community, our culture, our geographical area, and the prevailing economy often influence our values regarding water. For instance, if you are from an agricultural area, where your livelihood depends on the availability of water for your agricultural needs, you may rate the value or significance of water for your own life higher than someone whose livelihood is built around an entertainment industry such as running a cinema multiplex.


Take a few minutes to consider the various uses for water you have encountered in your life. Get out a pen and paper and list as many uses for water as you can. Compare your list to someone else’s list. How are they different? What do they have in common?

Review Questions

The following questions will help you assess your understanding of this section. There may be one, two, three, or even four correct answers to each question. To demonstrate your understanding, you should find all of the correct answers.

  1. Technology refers to
    1. computers, software, and computer peripherals
    2. changing the natural world to satisfy needs
    3. tools used by engineers to design systems
    4. pre-engineering courses taken in high school
  2. When looking at large-scale problems engineers should focus on
    1. the scientific aspects
    2. ethical aspects
    3. economic aspects
    4. legal aspects
  3. Engineering
    1. began as a twentieth-century invention
    2. has always been a human activity
    3. is a field first developed in Europe
    4. began with Alexander Graham Bell
  4. Engineers help design things that are
    1. practical and useful in our lives
    2. only useful to scientists
    3. too specialized to be useful
    4. not practical or economical
  5. One of the biggest challenges of engineering is to
    1. raise the standard of living while using natural resources
    2. keep the standard of living the same while sustaining natural resources
    3. keep the standard of living the same while using natural resources
    4. raise the standard of living while sustaining natural resources
  6. Engineering decisions must take into consideration
    1. internal systems
    2. natural systems
    3. man-made systems
    4. future systems
  7. Sustainable development is linked to
    1. basic needs
    2. freedom
    3. nutrition
    4. world peace
  8. Which of these influences our values regarding water
    1. culture
    2. cost
    3. cleanliness
    4. family
  9. Engineering achievements can have
    1. mistaken consequences
    2. unrealistic consequences
    3. no consequences
    4. unintended consequences
  10. When we use water we
    1. decrease its quality
    2. increase its quality
    3. do not affect its quality
    4. improve its quality

Review Answers

To Engineer Is Human

  1. b
  2. a,b,c,d
  3. b
  4. a
  5. d
  6. b,c
  7. a,b,c,d
  8. a,d
  9. d
  10. a

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