NRC Science Education Standards

Project 2061 Benchmarks

(www.npa.edu)

Content Standard: Unifying Concepts & Processes (pp. 115-119)

Fundamental concepts that underlie Systems, Order, & Organization include:

• A system is an organized group of related objects or components that form a whole.
• Systems can coexist, for example, of organisms, machines, fundamental particles, galaxies, ideas, numbers, transportation, and education.
• Systems have boundaries, components, resources flow (input and output), and feedback.
• Think and analyze in terms of systems.
• The idea of simple systems encompasses subsystems as well as identifying the structure and function of systems, feedback and equilibrium, and the distinction between open and closed systems.
• An understanding of regularities in systems, and by extension, the universe; they then can develop understanding of basic laws, theories, and models that explain the world.
• An assumption of order establishes the basis for cause-effect relationship and predictable.
• Physical systems can be described at different levels of organization-such as fundamental particles, atoms, and molecules.

Fundamental concepts that underlie Evidence, Models, & Explanation include:

• Evidence consists of observations and data on which to base scientific explanations.
• Using evidence to understand interactions allows individuals to predict changes in natural and designed systems.
• Models are tentative schemes or structures that correspond to real objects, events, or classes of events, and that have explanatory power.
• Models help scientists and engineers understand how things work.
• Models take many forms, including physical objects, plans, mental constructs, mathematical equations, and computer simulations.
• Scientific explanations incorporate existing scientific knowledge and new evidence from observations, experiments, or models into internally consistent, logical statements.
• Different terms, such as "hypothesis," "model," "law," "principle," "theory," and "paradigm" are used to describe various types of scientific explanations.
• Scientific explanations should more frequently include a rich scientific knowledge base, evidence of logic, higher levels of analysis, greater tolerance of criticism and uncertainty, and a clearer demonstration of the relationship between logic, evidence, and current knowledge.

Fundamental concepts that underlie Constancy, Change, and Measurement include:

• Although most things are in the process of becoming different-changing-some properties of objects and processes are characterized by constancy, including the speed of light, the charge of an electron, and the total mass plus energy in the universe.
• Interactions within and among systems result in change.
• Changes vary in rate, scale, and pattern, including trends and cycles.
• Energy can be transferred and matter can be changed.
• Changes in systems can be quantified.
• Evidence for interactions and subsequent change and the formulation of scientific explanations are often clarified through quantitative distinctions-measurement.
• Mathematics is essential for accurately measuring change.
• Different systems of measurement are used for different purposes.
• An important part of measurement is knowing when to use which system.
• Scale includes understanding that different characteristics, properties, or relationships within a system might change as its dimensions are increased or decreased.
• Rate involves comparing one measured quantity with another measured quantity.

Fundamental concepts that underlie Evolution & Equilibrium include:

• Equilibrium is a physical state in which forces and changes occur in opposite and off-setting directions
• Steady state, balance, and homeostasis also describe equilibrium states. Interacting units of matter tend toward equilibrium states in which the energy is distributed as randomly and uniformly as possible.

Content Standard A: Science as Inquiry (pp. 173-176)

Fundamental abilities and concepts that underlie the Abilities Necessary to Do Scientific Inquiry include:

• Identify questions and concepts that guide scientific investigations.
• Use technology and mathematics to improve investigations and communications.
• Formulate and revise scientific explanations and models using logic and evidence.
• Recognize and analyze alternative explanations and models.
• Communicate and defend a scientific argument.

Fundamental concepts that underlie the Understandings About Scientific Inquiry include:

• Historical and current scientific knowledge influence the design and interpretation of investigations and the evaluation of proposed explanations made by other scientists.
• Scientists rely on technology to enhance the gathering and manipulation of data.
• New techniques and tools provide new evidence to guide inquiry and new methods to gather data, thereby contributing to the advance of science.
• The accuracy and precision of the data, and therefore the quality of the exploration, depends on the technology used.
• Mathematics is essential in scientific inquiry. Mathematical tools and models guide and improve the posing of questions, gathering data, constructing explanations and communicating results.
• Scientific explanations must adhere to criteria such as:
  • a proposed explanation must be logically consistent;
  • it must abide by the rules of evidence; it must be open to questions and possible modification;
  • and it must be based on historical and current scientific knowledge.
  • In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge.
• The methods and procedures that scientists used to obtain evidence must be clearly reported to enhance opportunities for further investigation.

Content Standard B: Physical Science (pp. 176-181)

Fundamental concepts that underlie Chemical Reactions include:

• Chemical reactions occur all around us, for example in health care, cooking, cosmetics, and automobiles.
• Complex chemical reactions involving carbon-based molecules take place constantly in every cell in our bodies.
• Chemical reactions may release or consume energy.
• A large number of important reactions involve the transfer of either electrons (oxidation/reduction reactions) or hydrogen ions (acid/base reactions) between reacting ions, molecules, or atoms.
• Chemical bonds are broken by heat or light to form very reactive radicals with electrons ready to form new bonds.
• Radical reactions control many processes such as the presence of ozone and greenhouse gases in the atmosphere, burning and processing of fossil fuels, the formation of polymers, and explosions.
• Chemical reactions can take place in time periods ranging from the few femtoseconds (1- -15 seconds) required for an atom to move a fraction of a chemical bond distance to geologic time scales of billions of years.
• Reaction rates depend on how often the reacting atoms and molecules encounter one another, on the temperature, and on the properties- including shape-of the reacting species.

Fundamental concepts that underlie Conservation of Energy & the Increase in Disorder include:

• The total energy of the universe is constant.
• Energy can be transferred by collisions in chemical and nuclear reactions, by lightwaves and other radiations, and in many other ways.
• Energy can never be destroyed. As these transfers occur, the matter involved becomes steadily less ordered.
• All energy can be considered to be either kinetic energy, which is the energy of motion; potential energy, which depends on relative position; or energy contained by a field, such as electromagnetic waves.
• Heat consists of random motion and the vibrations of atoms, molecules, and ions.
• The higher the temperature, the greater the atomic or molecular motion.
• Everything tends to become less organized and less orderly over time. Thus, in all energy transfers, the overall effect is that the energy is spread out uniformly when we burn fuels.

Fundamental concepts that underlie Interactions of Energy & Matter include:

• Waves, including sound and seismic waves, waves on water, and light waves, have energy and can transfer energy when they interact with matter.
• Electromagnetic waves result when a charged object is accelerated or decelerated. Electromagnetic waves include radio waves (the longest wavelength), microwaves, infrared radiation (radiant heat), visible light, ultraviolet radiation, x-rays, and gamma rays.
• The energy of electromagnetic waves is carried in packets whose magnitude is inversely proportional to the wavelength.

Content Standard D: Earth & Space Science (pp. 187-190)

Fundamental concepts that underlie Energy in the Earth System include:

• Earth systems have internal and external sources of energy, both of which create heat.
• The sun is the major external source of energy.
• The outward transfer of earth's internal heat drives convection circulation in the mantle that propels the plates comprising earth's surface across the face of the globe.
• Heating of earth's surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents.
• Global climate is determined by energy transfer from the sun at and near the earth's surface. This energy transfer is influenced by dynamic processes such as cloud cover and the earth's rotation, and static conditions such as the position of mountain ranges and oceans.

Fundamental concepts that underlie Geochemical Cycles include:

• The earth is a system containing essentially a fixed amount of each stable chemical atom or element.
• Each element can exist in several different chemical reservoirs. Each element on earth moves among reservoirs in the solid earth, oceans, atmosphere, and organisms as part of geochemical cycles.
• Movement of matter between reservoirs is driven by the earth's internal and external sources of energy.
• These movements are often accompanied by a change in the physical and chemical properties of the matter.

Content Standard C: Life Science (pp. 181-187)

Fundamental concepts that underlie the Interdependence of Organisms include:

• The atoms and molecules on the earth cycle among the living and nonliving components of the biosphere.
• Energy flows through ecosystems in one direction, from photosynthetic organisms to herbivores to carnivores and decomposers.
• Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these organisms may generate ecosystems that are stable for hundreds or thousands of years.
• Living organisms have the capacity to produce populations of infinite size, but environments and resources are finite. This fundamental tension has profound effects on the interactions between organisms.
• Human beings live within the world's ecosystems. Increasingly, humans modify ecosystems as a result of population growth, technology, and consumption.
• Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening current global stability, and if not addressed, ecosystems will be irreversibly affected.

Content Standard F: Science in Personal & Social Perspectives (pp. 193-199)

Fundamental concepts that underlie Natural Resources include:

• Human populations use resources in the environment in order to maintain and improve their existence.
• Natural resources have been and will continue to be used to maintain human populations. -
• The earth does not have infinite resources; increasing human consumption places severe stress on the natural processes that renew some resources, and it depletes those resources that cannot be renewed.
• Humans use many natural systems as resources. Natural systems have the capacity to reuse waste, but that capacity is limited. Natural systems can change to an extent that exceeds the limits of organisms to adapt naturally or humans to adapt technologically.

Fundamental concepts that underlie Environmental Quality include:

• Natural ecosystems provide an array of basic processes that affect humans. Those processes include maintenance of the quality of the atmosphere, generation of soils, control of the hydrologic cycle, disposal of wastes, and recycling of nutrients.
• Humans are changing many of these basic processes, and the changes may be detrimental to humans.
• Materials from human societies affect both physical and chemical cycles of the earth. Many factors influence environmental quality.

Fundamental concepts that underlie Natural & Human-Induced Hazards include:

• Normal adjustments of earth may be hazardous for humans.
• Humans live at the interface between the atmosphere driven by solar energy and the upper mantle where convection creates changes in the earth's solid crust.
• As societies have grown, become stable, and come to value aspects of the environment, vulnerability to natural processes of change has increased. Human activities can enhance potential for hazards.
• Acquisition of resources, urban growth, and waste disposal can accelerate rates of natural change.
• Natural and human-induced hazards present the need for humans to assess potential danger and risk.
• Many changes in the environment designed by humans bring benefits to society, as well as cause risks.
• Students should understand the costs and trade-offs of various hazards-ranging from those with minor risk to a few people to major catastrophes with major risk to many people.
• The scale of events and the accuracy with which scientists and engineers can (and cannot) predict events are important considerations.

Fundamental concepts that underlie Science & Technology in Local, National, & Global Challenges include:

• Understanding basic concepts and principles of science and technology should precede active debate about the economics, policies, politics, and ethics of various science- and technology-related challenges. However, understanding science alone will not resolve local, national, or global challenges.
• Progress in science and technology can be affected by social issues and challenges. Funding priorities for specific health problems serve as examples of ways that social issues influence science and technology.
• Individuals and society must decide on proposals involving new research and the introduction of new technologies into society.
• Decisions involve assessment of alternatives, risks, costs, and benefits and consideration of who benefits and who suffers, who pays and gains, and what the risks are and who bears them.
• Students should understand the appropriateness and value of basic questions-"What can happen?"- "What are the odds?"-and "How do scientists and engineers know what will happen?"
• Humans have a major effect on other species. For example, the influence of humans on other organisms occurs through land use-which decreases space available to other species-and pollution-which changes the chemical composition of air, soil, and water.

Content Standard E: Science & Technology (pp. 190-193)

Fundamental concepts that underlie the Abilities of Technilogical Design include:

• Identify a problem or design an opportunity.
• Propose designs and choose between alternative solutions.
• Implement a proposed solution.
• Evaluate the solution and its consequences.
• Communicate the problem, process, and solution.

Fundamental concepts that underlie Understandings About Science & Technology include:

• Scientists in different disciplines ask different questions, use different methods of investigation, and accept different types of evidence to support their explanations.
• Many scientific investigations require the contributions of individuals from different disciplines, including engineering.
• New disciplines of science, such as geophysics and biochemistry often emerge at the interface of two older discplines.
• Technological solutions may create new problems. Science, by its nature, answers questions that may or may not directly influence humans. Sometimes scientific advances challenge people's beliefs and practical explanations concerning various aspects of the world.

Content Standard G: History & Nature of Science (pp. 200 & 201)

Fundamental concepts that underlie Science as a Human Endeavor include:

• Scientists have ethical traditions. Scientists value peer review, truthful reporting about the methods and outcomes of investigations, and making public the results of work. Violations of such norms do occur, but scientists responsible for such violations are censured by their peers.
• Scientists are influenced by societal, cultural, and personal beliefs and ways of viewing the world. Science is not separate from society but rather science is a part of society.

Fundamental concepts that underlie Nature of Scientific Knowledge include:

• Science distinguishes itself from other ways of knowing and from other bodies of knowledge through the use of empirical standards, logical arguments, and skepticism, as scientists strive for the best possible explanations about the natural world.
• Scientific explanations must meet certain criteria. First and foremost, they must be consistent with experimental and observational evidence about nature, and must make a ccurate predictions, when appropriate, about systems being studied.
• Scientific explanations should also be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public.
• Explanations on how the natural world changes based on myths, personal beliefs, religious values, mystical inspiration, superstition, or authority may be personally useful and socially relevant, but they are not scientific.
• Because all scientific ideas depend on experimental and observational confirmation, all scientific knowledge is, in principle, subject to change as new evidence becomes available.
• The core ideas of science such as the conservation of energy or the laws of motion have been subjected to a wide variety of confirmations and are therefore unlikely to change in the areas in which they have been tested.
• In areas where data or understanding are incomplete, such as the details of human evolution or questions surrounding global warming, new data may well ead to changes in current ideas or resolve current conflicts.
• In situations where information is still fragmentary, it is normal for scientific ideas to be incomplete, but this is also where the opportunity for making advances may be greatest.

Content Standard: Chapter 11, Common Themes

11A Systems:

• A system usually has some properties that are different from those of its parts, but appear because of the interaction of those parts.
• Understanding how things work and designing solutions to problems of almost any kind can be facilitated by systems analysis.
• In defining a system, it is important to specify its boundaries and subsystems, indicate its relation to other systems, and identify what its input and its output are expected to be.
• The successful operation of a designed system usually involves feedback. The stability of a system can be greater when it includes appropriate feedback mechanisms.
• Even in some very simple systems, it may not always be possible to predict accurately the result of changing some part or connection.

11B Models:

• The basic idea of mathematical modeling is to find a mathematical relationship that behaves in the same ways as the objects or processes under investigation.
• Computers have greatly improved the power and use of mathematical models by performing computations that are very long, very complicated, or repetitive.

11C Constancy and Change:

• A system in equilibrium may return to the same state of equilibrium if the disturbances it experiences are small.
• Graphs and equations are useful (and often equivalent) ways for depicting and analyzing patterns of change.
• In many physical, biological, and social systems, changes in one direction tend to produce opposing (but somewhat delayed) influences, leading to repetitive cycles of behavior.
• Most systems above the molecular level involve so many parts and forces and are so sensitive to tiny differences in conditions that their precise behavior is unpredictable, even if all the rules for change are known.
• Predictable or not, the precise future of a system is not completely determined by its present state and circumstances but also depends on the fundamentally uncertain outcomes of events on the atomic scale.

11D Scale:

• Representing large numbers in terms of powers of ten makes it easier to think about them and to compare things that are greatly different.
• Because different properties are not affected to the same degree by changes in scale, large changes in scale typically change the way that things work in physical, biological, or social systems.
• As the number of parts of a system grows in size, the number of possible internal interactions increases much more rapidly, roughly with the square of the number of parts.

Content Standard: Chapter 1, The Nature of Science

1A The Scientific World View:

• Scientists assume that the universe is a vast single system in which the basic rules are the same everywhere.
• Change and continuity are persistent features of science.
• In science, the testing, revising, and occasional discarding of theories, new and old never ends.
• Science is an ongoing process leads to an increasingly better understanding of how things work in the world but not to absolute truth.

1B Scientific Inquiry:

• Hypotheses are widely used in science for choosing what data to pay attention to and what additional data to seek, and for guiding the interpretation of the data (both new and previously available).
• Sometimes, scientists can control conditions in order to obtain evidence. When that is not possible for practical or ethical reasons, they try to observe as wide a range of natural occurrences as possible to be able to discern patterns.
• There are different traditions in science about what is investigated and how, but they all have in common certain basic beliefs about the value of evidence, logic, and good arguments. And there is agreement that progress in all fields of science depends on intelligence, hard work, imagination, and even chance.
• Scientists in any one research group tend to see things alike, so even groups of scientists may have trouble being entirely objective about their methods and findings. For that reason, scientific teams are expected to seek out the possible sources of bias in the design of their investigations and in their data analysis. Checking each other's results and explanations helps, but that is no guarantee against bias.
• In the short run, new ideas that do not mesh well with mainstream ideas in science often encounter vigorous criticism. In the long run, theories are judged by how they fit with other theories, the range of observations they explain, how well they explain observations, and how effective they are in predicting new findings.
• New ideas in science are limited by the context in which they are conceived; are often rejected by the scientific establishment; sometimes spring from unexpected findings; and usually grow slowly, through contributions from many investigators.

1C The Scientific Enterprise:

• Progress in science and invention depends heavily on what else is happening in society, and history often depends on scientific and technological developments.
• Science disciplines differ from one another in what is studied, techniques used, and outcomes sought, but they share a common purpose and philosophy, and all are part of the same scientific enterprise.
• Disciplines do not have fixed boundaries, and it happens that new scientific disciplines are being formed where existing ones meet and that some subdisciplines spin off to become new disciplines in their own right.
• Scientists can bring information, insights, and analytical skills to bear on matters of public concern.
• Scientists as a group can be expected to be no less biased than other groups are about their perceived interests.
• Funding influences the direction of science by virtue of the decisions that are made on which research to support.

Content Standard: Chapter 4, The Physical Setting

4D Structure of Matter:

• Atoms often join with one another in various combinations in distinct molecules or in repeating three-dimensional crystal patterns.
• An enormous variety of biological, chemical, and physical phenomena can be explained by changes in the arrangement and motion of atoms and molecules.
• The rate of reactions among atoms and molecules depends on how often they encounter one another, which is affected by the concentration, pressure, and temperature of the reacting materials.

4E Energy Transformations:

• Whenever the amount of energy in one place or form diminishes, the amount in other places or forms increases by the same amount.
• Heat energy in a material consists of the disordered motions of its atoms or molecules.
• In any interactions of atoms or molecules, the statistical odds are that they will end up with less order than they began-that is, with the heat energy spread out more evenly.
• Transformations of energy usually produce some energy in the form of heat, which spreads around by radiation or conduction into cooler places. Although just as much total energy remains, its being spread out more evenly means less can be done with it.
• Different energy levels are associated with different configurations of atoms and molecules. Some changes of configuration require an input of energy whereas others release energy.

4C Processes that Shape the Earth:

• Plants alter the earth's atmosphere by removing carbon dioxide, using the carbon to make sugars and releasing oxygen. This process is responsible for the oxygen content of the air.
• The slow movement of material within the earth results from heat flowing out from the deep interior and the action of gravitational forces on regions of different density.

4B The Earth:

• Life is adapted to conditions on the earth, including the force of gravity that enables the planet to retain an adequate atmosphere, and an intensity of radiation from the sun that allows water to cycle between liquid and vapor.
• Weather (in the short run) and climate (in the long run) involve the transfer of energy in and out of the atmosphere.
• Solar radiation heats the land masses, oceans, and air.
• Transfer of heat energy at the boundaries between the atmosphere, the land masses, and the oceans results in layers of different temperatures and densities in both the ocean and atmosphere.

Content Standard: Chapter 5, The Living Environment

5D Interdependence of Life:

• Ecosystems can be reasonably stable over hundreds or thousands of years. As any population of organisms grows, it is held in check by one or more environmental factors: depletion of food or nesting sites, increased loss to increased numbers of predators, or parasites. If a disaster such as flood or fire occurs, the damaged ecosystem is likely to recover in stages that eventually result in a system similar to the original one.
• Like many complex systems, ecosystems tend to have cyclic fluctuations around a state of rough equilibrium. In the long run, however, ecosystems always change when climate changes or when one or more new species appear as a result of migration or local evolution.
• Human beings are part of the earth's ecosystems.
• Human activities can, deliberately or inadvertently, alter the equilibrium in ecosystems.

5E Flow of Matter and Energy:

• Layers of energy-rich organic material have been gradually turned into great coal beds and oil pools by the pressure of the overlying earth.
• By burning these fossil fuels, people are passing most of the stored energy back into the environment as heat and releasing large amounts of carbon dioxide.
• The chemical elements that make up the molecules of living things pass through food webs and are combined and recombined in different ways.
• At each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat.
• Continual input of energy from sunlight keeps the process(Flow of Matter and Energy) going.

Content Standard: Chapter 7, Human Society

7C Social Change:

• The size and rate of growth of the human population in any location is affected by economic, political, religious, technological, and environmental factors. Some of these factors, in turn, are influenced by the size and rate of growth of the population.
• The decisions of one generation both provide and limit the range of possibilities open to the next generation.
• Mass media, migrations, and conquest affect social change by exposing one culture to another.
• To various degrees, governments try to bring about social change or to impede it through policies, laws, incentives, or direct coercion. Sometimes such efforts achieve their intended results and sometimes they do not.

7D Social Trade-offs:

• Benefits and costs of proposed choices include consequences that are long-term as well as short-term, and indirect as well as direct.
• The more remote the consequences of a personal or social decision, the harder it usually is to take them into account in considering alternatives.
• Benifits and costs may be difficult to estimate.
• In deciding among alternatives, a major question is who will receive the benefits and who (not necessarily the same people) will bear the costs.
• Social trade-offs are often generational:
  • The cost of benefits received by one generation may fall on subsequent generations.
  • The cost of a social trade-off is sometimes borne by one generation although the benefits are enjoyed by their descendants.

7E Political and Economic Systems:

• In the free-market model, the control of production and consumption is mainly in private hands. The best allocation of resources is believed to be achieved by talent, and hard work are expected to be rewarded with success and wealth.
• Government's role is primarily to protect political and economic freedoms for society as a whole-even at the cost of some individual or group material benefits.
• In the central-planning model, production and consumption are controlled by the government.
• The best allocation of resources is thought to be achieved through government planning by experts.
• Dedication to the good of the society as a whole is expected to motivate initiative, talent, and hard work.
• The main purpose of government is to promote comparable welfare for all individuals and groups-even at the cost of some individual and group freedoms.
• In practice, countries make compromises with regard to economic models. Central planning has to allow for some individual initiative, and markets have to provide some protection for unsuccessful competitors. The countries of the world use elements of both systems and are neither purely free-market nor entirely centrally controlled. Countries change, some adopting more free-market policies and practices, others more central-planning ones, and still others doing some of each.

7F Social Conflict:

• Conflict between people or groups arises from competition over ideas, resources, power, and status.
• Social change, or the prospect of it, promotes conflict because social, economic, and political changes usually benefit some groups more than others. That, of course, is also true of the status quo.
• Conflicts are especially difficult to resolve in situations in which there are few choices and little room for compromise. Some informal ways of responding to conflict-use of pamphlets, demonstrations, cartoons, etc.-may sometimes reduce tensions and lead to compromise but at other times they may be inflammatory and make agreement more difficult to reach.
• Conflict within a group may be reduced by conflict between it and other groups.
• Intergroup conflict does not necessarily end when one segment of society gets a decision in its favor, for the "losers" may then work all the harder to reverse, modify, or circumvent the change. Even when the majority of the people in a society agree on a social decision, the minority who disagree must be protected from oppression, just as the majority may need protection against unfair retaliation from the minority.

7G Global Interdependence:

• The wealth of a country depends partly on the effort and skills of its workers, its natural resources, and the capital and technology available to it.
• The wealth of a country also depends on the balance between how much its products are sought by other nations and how much of other nations' products it seeks.
• Even if a country could produce everything it needs for itself, it would still benefit from trade with other countries.
• Because of increasing international trade, the domestic products of any country may be made up in part by parts made in other countries.
• The international trade picture is often complicated by political motivations taking priority over economic ones.
• Migration across borders, temporary and permanent, legal and illegal, plays a major role in the availability and distribution of labor in many nations. It can bring both economic benefits and political problems.
• The growing interdependence of world social, economic, and ecological systems does not always bring greater worldwide stability and often increases the costs of conflict.

Content Standard: Chapter 8, The Designed World

8B Materials and Manufacturing:

• Waste management includes considerations of quantity, safety, degradability, and cost. It requires social and technological innovations, because waste-disposal problems are political and economic as well as technical.
• Scientific research identifies new materials and new uses of known materials.
• Increased knowledge of the molecular structure of materials helps in the design and synthesis of new materials for special purposes.

8C Energy Sources and Use:

• A central factor in technological change has been how hot a fire could be made:
  
  • The discovery of new fuels, the design of better ovens and furnaces, and the forced delivery of air or pure oxygen have progressively increased the available temperature
  • At present, all fuels have advantages and disadvantages so that society must consider the trade-offs among them.
  • Nuclear reactions release energy without the combustion products of burning fuels, but the radioactivity of fuels and by-products poses other risks, which may last for thousands of years.
  • Industrialization brings an increased demand for and use of energy. Such usage contributes to the high standard of living in the industrially developing nations but also leads to more rapid depletion of the earth's energy resources and to environmental risks associated with the use of fossil and nuclear fuels.
  • Decisions to slow the depletion of energy sources through efficient technology can be made at many levels, from personal to national, and they always involve trade-offs of economic costs and social values.

Content Standard: Chapter 12, Habits of Mind

12A Values and Attitudes:

• Know why curiosity, honesty, openness, and skepticism are so highly regarded in science and how they are incorporated into the way science is carried out; exhibit those traits in their own lives and value them in others.
• View science and technology thoughtfully, being neither categorically antagonistic nor uncritically positive.

12D Communication Skills:

• Choose appropriate summary statistics to describe group differences, always indicating the spread of the data as well as the data's central tendencies.
• Participate in group discussions on scientific topics by restating or summarizing accurately what others have said, asking for clarification or elaboration, and expressing alternative positions.
• Use tables, charts, and graphs in making arguments and claims in oral and written presentations.

12E Critical-Response Skills:

• Notice and criticize arguments based on the faulty, incomplete, or misleading use of numbers, such as in instances when:
  • average results are reported, but not the amount of variation around the average
  • a percentage or fraction is given, but not the total sample size (as in "9 out of 1- dentists recommend...")
  • absolute and proportional quantities are mixed (as in "3,400 more robberies in our city last year, whereas other cities had an increase of less than 1%)
  • results are reported with overstated precision (as in representing 13 out of 19 students as 68.42%)
  • Check graphs to see that they do not misrepresent results by using inappropriate scales or by failing to specify the axes clearly.
  • Wonder how likely it is that some event of interest might have occurred just by chance.
  • Insist that the critical assumptions behind any line of reasoning be made explicit so that the validity of the position being taken-whether one's own or that of others-can be judged.
  • Be aware, when considering claims, that when people try to prove a point, they may select only the data that support it and ignore any that would contradict it.
  • Suggest alternative ways of explaining data and criticize arguments in which data, explanations, or conclusions are represented as the only ones worth consideration, with no mention of other possibilities. Similarly, suggest alternative trade-offs in decisions and designs and criticize those in which major trade-offs are not acknowledged.