Chapter 4: Scientific Literacy: A Modest ProposalBack to table of contents
James Trefil and Robert M. Hazen
In the next day or two, science will make the news with headlines like “Swine Flu Reaches Pandemic Stage” or “Magnitude 6.5 Earthquake Rocks China.”1 Genetic engineering, water pollution, designer drugs, planetary exploration, global warming, and dozens of other topics are an essential part of the fabric of the twenty-first century. Climate change, natural resources, health, environment, energy, homeland security: these and many other scientific and technological issues directly affect us all and dominate national debates about our priorities and our future. Every citizen needs to understand these issues. To do so, every citizen must be scientifically literate.
Undergraduate science education plays a central role in this national imperative. For millions of American students, college represents the last opportunity for formal science education. Our modest proposal for achieving scientific literacy recommends reaching out to non-science majors with courses that place science—in its broadest sense—within a context that is relevant and accessible to all undergraduates.
CHANGING ATTITUDES TOWARD SCIENTIFIC LITERACY
The quest for effective and relevant science education for the general public spans nearly a century. The influential education reformer John Dewey penned one of the first theoretical justifications for incorporating science into the general curriculum. Dewey formulated a rationale for science education that resonates in the educational establishment still today: “Contemporary civilization rests so largely upon applied science that no one can really understand it who does not grasp something of the scientific method. . . . The formation of scientific habits of mind should be the primary aim of the science teacher in the high school” (Dewey, 1909).
During the 1920s and 1930s, these ideas captured the attention of educational philosophers and precipitated the inclusion of science in the curriculum. Implicit in this movement was the idea that a magic bullet called the “scientific method” would somehow transform students into logical, reasoning human beings. University of Wisconsin educator I. C. Davis offered a telling definition of the successful student:
We can say that an individual who has a scientific attitude will (1) show a willingness to change his opinion on the basis of new evidence; (2) will search for the whole truth without prejudice; (3) will have a concept of cause and effect relationships; (4) will make a habit of basing judgment on fact; and (5) will have the ability to distinguish between fact and theory. (Davis, 1935)
Experience has shown that these education goals, however worthy in the abstract, are simply unrealistic. At some point, we need to ask ourselves what we can reasonably expect from the actual students who sit in our classrooms. To be sure, a small percentage of students will excel, and some will go on to distinguished careers in science and technology fields. But what about the great majority of students who will go on to become doctors, lawyers, teachers, and business leaders? What about our future politicians, who will have to vote on issues related to science and technology? What should be the role of science education in their lives? We argue that undergraduate science education should ensure that every student is scientifically literate.
WHAT IS SCIENTIFIC LITERACY?
We define scientific literacy as the matrix of knowledge needed to understand enough about the physical universe to deal with issues in the news and elsewhere. This definition is based solely on considerations of how citizens actually use science. Just as one does not need to be an economist to read the business section of the newspaper or a lawyer to read about a pending Supreme Court case, one does not need to be a scientist to be scientifically literate.
What everyone does need to know is a mix of facts, vocabulary, concepts, history, and philosophy (Hazen & Trefil, 1991; Hirsch, 1987; Trefil & Hazen, 2007). Scientific literacy is not the specialized stuff of experts but the more general, relevant knowledge used in political discourse and everyday life. Everyone should understand the nature of science as a way of knowing, or the types of questions science can and cannot answer. They should understand the role of measurement, experiment, and mathematical analysis in science and the strengths and limitations of science in resolving complex societal debates. Scientifically literate citizens should also know core concepts and basic vocabulary related to matter, energy, forces, and motions. They should be conversant in topics such as the nature of atoms and chemical reactions, the formation of planets and stars, the processes of plate tectonics and Earth cycles, and the fundamental biological concepts of cells, the genetic code, and evolution.
The knowledge that constitutes scientific literacy is broad but not deep. Consequently, this definition of scientific literacy will seem minimal, perhaps even inadequate, to those who insist that everyone must understand science at a complex level. This attitude was expressed, for example, by the late New York University physicist Morris Shamos (1995), who distinguished between what he called cultural, functional, and “true” scientific literacy. The fundamental problem with this approach to science education is the belief that an individual cannot be “truly” scientifically literate unless he or she can independently draw conclusions about scientific issues using the same kind of reasoning that a professional scientist would employ. From Shamos’s viewpoint, having enough background to understand a newspaper article on fossils or superconductors or the greenhouse effect is not enough. This position echoes John Dewey’s “scientific habits of mind” yet does not recognize (as Dewey implicitly did) that such a goal is appropriate only for the small fraction of students who major in science. Such discrepancy arises over and over again in the debate about science education and deserves closer inspection.
Individuals’ attitudes toward mathematics might also serve as a metric for their opinions on the nature of scientific literacy. Shamos writes, “It is unrealistic to believe that one can fully appreciate the broad reach of science without seeing firsthand the role played in it by mathematical reasoning” (Shamos, 1995). This attitude, which might be translated as, “I had to learn a lot of difficult math to become a scientist, so you should learn it, too,” is taken to an absurd extreme by some faculty, who argue that everyone should study calculus at the university level before studying science. To deny students an understanding of science because they do not know mathematics is no more sensible than denying them War and Peace because they cannot read Russian.
A common fallacy in science education is that every student should “think like us.” We have all encountered students who were highly intelligent individuals, accomplished in many areas, but who had extreme difficulty in grasping the quantitative thought process of science. Education psychologist Howard Gardner (2006) underscores the problem with his analysis of different types of intelligences (including linguistic, logical-mathematical, spatial, bodily-kinesthetic, interpersonal, and intrapersonal intelligence). Of these diverse capabilities, only logical-mathematical and spatial reasoning contribute centrally to the traditional scientific process. To select arbitrarily the intelligences appropriate to science and say that everyone has to excel in them makes no more sense than requiring that everyone be able to write a symphony or play sports at a professional level.
This brings us back to the definition of scientific literacy. We want citizens who are able to approach the scientific aspect of public issues with the same level of competence that they have in other areas. What, precisely, does our model citizen have to know to meet our goal?
Some would propose that everyone should be able to “apply critical reasoning” and “come to independent conclusions.” By this standard, average citizens are supposed to be able to look at scientific arguments, listen to the competing experts, and use their scientific knowledge and education to decide which side is right. This is a noble ambition, but let us be blunt: this expectation is unrealistic. For one, scientific issues today and in the foreseeable future are sufficiently complex that most Ph.D. scientists are unprepared to perform this analytical task. Indeed, Ph.D. scientists themselves are often scientifically illiterate in most fields except their personal specialties. Thus, short of requiring everyone to have advanced degrees in everything, we see no way to achieve this goal.
Accordingly, we need to acknowledge the difference between scientific competence and scientific literacy. If our goal is to train a new generation of engineers, scientists, and technicians, then we want to teach people how to do science. But no matter how technological the economy becomes, most people will never need to do science for a living. Everyone, however, will need to be scientifically literate to function effectively as a citizen. The distinction between the needs of these two populations is important and largely negates arguments for scientific literacy based on topical and mathematical rigor.
Thinking “like us” does not appear to be of much help in dealing with public issues. After all, the amount of information a citizen needs to enter a public debate is minimal and not at all like that of a science specialist. A “think like us” approach does little to promote scientific literacy. In essence, we must avoid confusing the difference between doing science and using science.
A MODEST PROPOSAL
What can educators do? For the past two decades, we have promoted a science education strategy designed to bring every citizen as far along in science as he or she is capable of going, based on two simple, self-evident propositions:
- We have to teach the students we have, not the students we wish we had.
- If we expect students to know something, we have to tell them what it is.
Before proposing a detailed outline of the core content of a scientific literacy course, we will start off with a general discussion of these two propositions.
Teach the Students We Have
Much of the unhappiness we see with respect to teaching non-scientists comes from the failure to honor this first proposition. If we decide to teach nonscientists (and not everyone has to make that decision), we are going to get a mixed bag of students. A small group (probably less than a third in most classes) will be genuinely excited by the subject. A larger group of students (between a third and a half in our experience) will be less engaged but will put in the time necessary to get a good grade. And, inevitably, a final group of students will lack the ability or the ambition to succeed.
Collectively, these are the students we have to teach. Some will “get it” easily, and others will struggle, but the job of the teacher is to help each student as far along the path to scientific literacy as possible. This reality often means that some worthwhile goals have to be put on the back burner while we concentrate on the science. We cannot, for example, spend a lot of time correcting a student’s English or writing skills; we do not have enough time.
More important, we probably are not going to be able to take on the twin problems of scientific illiteracy and innumeracy (Paulos, 1988) at the same time. Not only will many of our students have intelligences other than those associated with mathematical skills, but they will also suffer from varying degrees of math phobia. If we want students to engage with science, then we cannot try to communicate by using lots of equations. This constraint is not necessarily a problem because the basic ideas of science can be easily presented without equations.
Ultimately, we suspect that the problem with the first proposition is that many scientists secretly yearn for a diminished world in which Gardner’s many intelligences are shrunk down to only one or two (the one or two they are good at, of course). But the essence of being a good scientist is the ability to recognize the realities of the external world––in this case, a world in which our students have many kinds of intelligence but share a common need for scientific literacy.
Tell Students What We Want Them to Know
The second proposition also seems self-evident but is profoundly out of line with a major school of thought in science education. This misguided school holds that something exists called the “scientific method” (or, as Dewey put it, a “scientific habit of mind”) and that all we have to do is teach students this scientific process and they will grasp everything else about science on their own. This approach is most commonly manifest in ill-founded requirements that oblige every undergraduate non-science major to take an introductory, two-semester lab sequence in a single branch of science: Physics 101 and 102, for example. Such courses may illustrate the “scientific method,” but they will also leave graduates ill-equipped to deal with most real-world problems such as energy resources, environmental change, and global health policy, all of which require a basic understanding of concepts in chemistry, geology, and biology, as well as physics.
This point exemplifies a long-standing issue in science education: the conflict between method and content. What we define as scientific literacy is on the content side of this dichotomy, while Dewey’s paradigm is on the method side. We believe that the focus on teaching the “scientific method” is a deeply flawed approach for non-science majors. When we want to annoy our colleagues, we call it the “teach them Newton’s laws and they’ll derive molecular biology on the way home” school of thought. Such a thing as the “scientific method” does exist, but knowledge of this method is only a small first step on the road to our vision of scientific literacy.
Two arguments highlight the fallacy of the method school of thought. First, if we applied this argument to any other field of study, its failings would be transparent. If we argued for the existence of a “language method,” such that studying French would provide easy access to Czech or Urdu, we would all recognize that the argument does not accurately describe how the learning of languages works. If we want to read Czech, we do not study French; we study Czech. Similarly, if we want to discuss stem cells, we do not study climate models; we study molecular and developmental biology.
Second, computers are producing dramatic changes in the way that science is being done. The simple experiments one can do in a university lab class— which are supposed to teach the scientific method—no longer have much relevance as far as many real problems in science are concerned. Consequently, the “scientific method” may become increasingly irrelevant to public discussions. A concentration on method rather than the actual content of scientific literacy, then, is likely to produce students ready to cope with Galileo’s rolling balls in a world dominated by genome sequencing and global climate modeling.
THE GREAT IDEAS OF SCIENCE
Our approach to scientific literacy in general, and undergraduate science education in particular, focuses on content. We argue that approximately twenty “great ideas of science” (Table 1) collectively provide the foundation for scientific literacy (Hazen & Trefil, 1991; Trefil, 2008; Trefil & Hazen, 2007). Each of these ideas represents a core scientific concept that integrates a vast body of observation, experiment, and theory. Each reflects everyday experience and observations and thus can be presented in everyday language without equations or mathematical abstraction. Collectively, the great ideas span all the branches of science and provide a comprehensive view of the processes of the natural world.
The list of great ideas, while not immutable, includes overarching concepts that unify nearly all observations of the natural world made by scientists of every specialty. When the initial list of twenty great ideas was first proposed (Hazen & Trefil, 1991), Science conducted a survey of its readers, hundreds of whom proposed additions, deletions, or modifications to the list (Culotta, 1991; Pool, 1991). Predictably, most specialists wanted more content in their field: physicists, chemists, geologists, and biologists alike claimed that their specialties deserved a greater fraction of core concepts. Nevertheless, the principle that science rests on a few overarching concepts, including energy, matter, and evolution, was not called into question.
What follows, then, is our proposed list of twenty great ideas of science— the foundation upon which any undergraduate science curriculum should be based.
Table 1: Twenty Great Ideas of Science
Science is a way of asking and answering questions about the physical universe. A deep truth about the universe is that it behaves in regular and predictable ways. The underlying assumption behind the scientific endeavor is that the universe obeys general laws that are discoverable by the human mind. Nevertheless, science is not the only way, nor always the best way, to gain an understanding of the world in which we live. Science complements philosophy, religion, and the arts as ways to gain insight into the cosmos and our place in it.
Discovering regularities in nature requires that we observe the phenomena around us—the first step in the idealized scientific method. Once we understand those regularities, we can devise models, make predictions about what will happen, and observe nature and perform experiments to see if those predictions are correct.
2. Forces and Motion
One set of laws describes motions on Earth and in space. The science of motions developed when our ancestors recognized regularities in the movements of objects in the sky and on land. Isaac Newton proposed his universal laws to define the relationships between motions and forces such as gravity.
Energy is conserved and always goes from more-useful to less-useful forms. We do work when we exert a force over a distance. Energy is defined as the ability to do work (that is, to exert a force over a distance). Two laws of thermodynamics unify the study of energy. The first law recognizes that energy comes in many forms, including motion, heat, light, and varied kinds of stored (or potential) energy. Energy can change from any one of these forms to another, but the total amount of energy in a closed system cannot increase or decrease.
The second law of thermodynamics deals with the direction of the universe. Heat left to itself flows in only one direction, from hot to cold. Similarly, systems left to themselves always become more disordered with time.
4. Electricity and Magnetism
Electricity and magnetism are two aspects of the same force. Electrical charge can be either positive or negative, and the electrical force operates in such a way that the force between like charges is repulsive, whereas the force between unlike charges is attractive. Magnets have north and south poles, and the magnetic force is such that like poles repel one another while unlike poles attract. Isolated magnetic poles do not occur in nature: whenever we find a north pole, we also find a south pole.
Electrical and magnetic forces appear to be different, but whenever electrical charges move (that is, whenever an electric current flows) a magnetic field is produced (the working principle of the electromagnet and the electric motor). Conversely, whenever a magnetic field changes near a material that conducts electricity, an electric current is produced in that material (the working principle of the electric generator).
Equations that summarize the behavior of electric and magnetic phenomena predict the existence of electromagnetic waves––energy waves that move at the speed of light. Radio, microwave, infrared radiation, visible light, ultraviolet light, X-rays, and gamma rays are examples of electromagnetic waves.
All of the matter around us is made of atoms. The world holds two kinds of materials: those that can be broken down by chemical means (compounds) and those that cannot (chemical elements). Each element is composed of small units called atoms, and all other materials are made by combining atoms. Each atom has a massive, positively charged nucleus surrounded by negatively charged electrons.
6. Quantum Mechanics
Matter and energy come in discrete units; we cannot measure anything without changing it. At the scale of the atom, every property—mass, energy, spin, and more—comes in discrete bundles called quanta. At the scale of the atom, any measurement must involve a change of the quantum state of the object being measured. Therefore, we cannot measure an object at the scale of the atom without changing it in the process of measurement.
7. Chemical Bonding
Atoms bind together by the rearrangement of electrons. Everyday materials form from different combinations of atoms, which bond together by rearranging the atoms’ outermost electrons. Electrons produce a bond between atoms in three ways: (1) one atom can transfer an electron permanently to another to produce an ionic bond; (2) two atoms can share a pair of electrons to produce a covalent bond; (3) each atom can give up an electron, which is then shared by all the atoms to produce a metallic bond.
The properties of a material depend on how its atoms are arranged. The properties of a material depend on the type of bond holding its atoms together, as well as the arrangement of those atoms. For example, electrical properties depend on how strongly electrons are locked into their bonds. In a metal, electrons are free to move when subjected to outside forces, so electrical current flows easily. Metals are thus electrical conductors. In most plastics or ceramics, on the other hand, electrons are locked tightly into covalent or ionic bonds. Such materials are called electrical insulators.
9. The Nucleus of the Atom
Nuclear energy comes from the conversion of mass. The nucleus of the atom is a dense collection of particles that carries most of the mass of the atom. In nuclear reactions, some of this mass may be converted to energy via Einstein’s famous equation E = mc2. Nuclei with the same number of protons but different numbers of neutrons are called isotopes of one another. Some isotopes are unstable and undergo a process of disintegration known as radioactive decay.
Energy can be derived from nuclei by fusion (the coming together of small nuclei to form larger ones) or fission (the splitting of large nuclei into smaller ones). When the mass of the final products is less than that of the initial nuclei, the difference is converted into energy.
10. Particle Physics
All matter is really made of quarks and leptons. Atoms are made of even smaller
particles, including leptons (of which the electron is one example) and quarks (which combine in groups of three to make protons and neutrons).
Stars, which use nuclear fusion to convert mass into energy, must eventually burn out. Stars are born in the gravitational collapse of dust clouds in space. The temperature and pressure at a star’s center increase until nuclear fusion reactions start, converting hydrogen into helium in the process. The energy from these reactions creates a pressure that counteracts the force of gravity and stabilizes the star.
The sun and other stars spend most of their lives in this hydrogen-burning phase. The sun will eventually consume its hydrogen fuel and will collapse to become a white dwarf star (in another 5.5 billion years). Stars much more massive than the sun can become unstable, exploding into a supernova. Debris from a supernova is blown into space, where it is incorporated into new generations of stars.
12. The Big Bang
The universe was born at a specific time in the past, and it has been expanding ever since. American astronomer Edwin Hubble discovered that matter in the universe is clumped together in large collections of stars called galaxies and that galaxies are moving apart from one another. The Hubble expansion implies that the universe began at a specific time in the past (about 14 billion years ago) and has been expanding and cooling ever since. Studies of the expanding universe reveal that visible matter represents only a small fraction of what the universe contains. Over 90 percent of the cosmos is made of poorly understood material called “dark matter” and “dark energy.”
Every observer sees the same laws of nature. Albert Einstein’s theory of relativity comes in two parts: special relativity, which deals with observers moving at constant velocities; and general relativity, which deals with observers who are accelerating. Among the paradoxical findings of special relativity are (1) moving clocks slow down, (2) moving objects become more massive, (3) moving objects appear to shorten in the direction of their motion, and (4) mass and energy are equivalent, as stated in the famous equation E = mc2.
Earth and other objects in the solar system formed 4.5 billion years ago from a great cloud of dust and gas. The sun and planets of our solar system formed from the gravitational collapse of a nebula, an immense cloud in space. More than 99 percent of the mass of this nebula formed the sun, while most of the remainder formed the planets. The four inner planets closest to the sun (Mercury, Venus, Earth, and Mars) are relatively small and rocky. The outer four planets, which formed in colder regions farther from the sun where gases could condense, are gas giants formed primarily of the elements hydrogen and helium.
15. Plate Tectonics
Earth’s surface changes constantly because of convection of hot rocks deep within the planet. Earth is layered like an onion. The central core consists of dense iron and nickel; the mantle is composed of minerals rich in silicon, oxygen, and magnesium; and the outermost layer is a thin crust. Earth’s surface is separated into thin, brittle, tectonic plates that move around in response to convection in the hot mantle. Continents are the uppermost layer of these plates.
The continuous motion of the plates constantly changes the surface features of the planet.
16. Earth Cycles
Earth operates in many cycles. Earth’s rocks, water, and atmosphere operate in cycles in which energy flows and atoms are used over and over again. Water, for example, evaporates from the oceans and falls as rain on land, eventually flowing back into the ocean, as either a surface river or an underground aquifer. Over long periods of time, more of Earth’s water can be taken up in ice caps and glaciers during ice ages, or can be put back into the oceans during periods of global warming.
All living things are made from cells, the chemical factories of life. Life is based on chemical reactions, which take place in complex structures called cells. Cells are the fundamental unit of life, and all cells arise from preexisting cells. Each cell is analogous to a chemical factory. Chemical reactions in a cell are controlled by protein molecules that serve as enzymes, and the information for building those molecules is coded in stretches of DNA called genes.
18. Molecular Genetics
All life is based on the same genetic code. All known life forms on Earth, from bacteria to humans, use the same DNA code and the same molecular machinery to produce the proteins that run chemical reactions essential to life. This fact is the basis for genetic engineering, a technique that already plays a major role in agriculture and medicine. In genetic engineering, a gene from one organism is inserted into the DNA of another organism.
All forms of life evolved by natural selection. Scientists divide the development of life on Earth into two stages: chemical evolution, which involves the development of life from inorganic materials; and evolution by natural selection, which describes the process by which the first early life form produced the diversity of modern life. Natural selection is associated with the discoveries of Charles Darwin and is what most people mean by the term evolution.
Evolution by natural selection depends on two familiar characteristics of living things: first, populations exhibit variations in traits (so that, for example, some rabbits can run faster than others); second, individuals compete (so that fast rabbits are more likely to survive and reproduce). Over many generations, this selection process produces new species. Evidence for evolution by natural selection comes from the fossil record and from the examination of genes in the DNA of modern life forms.
Ecosystems are interdependent communities of living things. Ecosystems include all living things in a specific area, together with their material surroundings. Plants and animals within an ecosystem often depend on each other in complex ways, so it is not usually possible to change one part of the system without changing other parts as well. Studies of past ecosystems show that both the kinds of plants and animals present in a system and the relationships among different organisms change over time.
Human activities, such as increased burning of carbon-based fuels, may gradually change the composition of Earth’s atmosphere. These changes may, in turn, alter the global climate and, hence, Earth’s ecosystems in ways and extents that are difficult to predict with certainty.
Science educators have implemented many approaches to engaging undergraduate non-science majors, including traditional discipline-based lab courses; seminars on broad topics such as energy, evolution, the environment, or forensics; explorations of scientific current events and public policy; and courses that explore science from historical and/or philosophical perspectives. In the hands of a dedicated and dynamic teacher, any of these strategies has the potential to captivate and enlighten students, and many of these approaches are used to great effect at colleges and universities with small classes and frequent student-faculty interactions.
The “great ideas of science” curriculum represents another undergraduate option that integrates many of the best aspects of other course strategies but that may be better suited to the needs of a large community of non-science majors. The great ideas provide students with a broad perspective on all scientific disciplines and underscore the impact of those varied fields on modern society. Each great idea can be illustrated with everyday experiences and current events, and each can be presented in a framework that recognizes a rich historical and philosophical context. The great ideas curriculum also underscores the strong linkages in concept and content among the different branches of science: forces, motion, energy, matter, atoms, evolution, and many other topics appear again and again throughout the curriculum and thus reinforce the importance of a few core ideas.
Most important, by introducing students to the full sweep of the sciences, we provide them with a firm foundation for lifelong learning in science. Students will thus have the opportunity to appreciate the role of science in their lives, to apply that understanding to personal decisions related to health and environment, to foster learning in their children, and to share in the excitement and wonder of the greatest ongoing human adventure—the adventure of scientific discovery.
1. This essay is adapted in part from Robert M. Hazen and James Trefil, Science Matters: Achieving Scientific Literacy, 2nd ed. (New York: Anchor, 2009); James Trefil and Robert M. Hazen, The Sciences: An Integrated Approach, 6th ed. (Hoboken, N.J.: Wiley, 2010); and James Trefil, Why Science? (New York: Teachers College Press, 2008).
Culotta, E. 1991. Science’s 20 greatest hits take their lumps. Science 251: 1308–1309.
Davis, I. C. 1935. The measurement of scientific attitudes. Science Education 19:117–122.
Dewey, J. 1909. Symposium on the purpose and organization of physics teaching in secondary schools. School Science and Mathematics 9:291–292.
Gardner, H. 2006. Multiple Intelligences: The Theory in Practice. New York: Basic Books.
Hazen, R. M., and J. Trefil. 2009. Science Matters: Achieving Scientific Literacy, 2nd ed. New York: Anchor.
Hirsch, Jr., E. D. 1987. Cultural Literacy: What Every American Needs to Know. New York: Houghton Mifflin.
Paulos, J. A. 1988. Innumeracy: The Consequences of Mathematical Illiteracy. New York: Farrar, Straus and Giroux.
Pool, R. 1991. Science literacy: The enemy is us. Science 251:266–267.
Shamos, M. H. 1995. The Myth of Scientific Literacy. Rutgers, N.J.: Rutgers University Press.
Trefil, J. 2008. Why Science? New York: Teachers College Press.
———, and R. M. Hazen. 2010. The Sciences: An Integrated Approach. 6th ed. Hoboken, N.J.: Wiley.