10G/H2 ( Grades: 9-12 ): Ernest Rutherford of New Zealand and his colleagues discovered that the heavy radioactive element uranium spontaneously splits itself into a slightly lighter nucleus and a very light helium nucleus, leading to the realization that one kind of atom may change into another kind, and that therefore an atom must be made up of smaller parts.
10G/H3a ( Grades: 9-12 ): Otto Hahn and Fritz Strassmann, German chemists, found that when they struck uranium with a beam of neutrons, barium was unexpectedly produced. Austrian physicist Lise Meitner, who had earlier worked with Hahn and Strassmann on the decay patterns of uranium, was the first to suggest that the barium could have resulted from the splitting of the uranium nucleus into two middleweight nuclei and one or two extra neutrons.
10G/H3c ( Grades: 9-12 ): Enrico Fermi, an Italian working with colleagues in the United States, showed that the extra neutrons trigger more fissions in uranium nuclei and so create a sustained chain reaction in which a prodigious amount of energy is given off.
10G/H4a ( Grades: 9-12 ): A massive effort went into developing the technology for the production of nuclear fission bombs used against Japan in World War II. The hydrogen bomb, which uses nuclear fusion, was developed shortly after World War II. Another important development of this era was the nuclear reactor, in which nuclear energies are released in a controlled fashion for the production of electrical energy.
10G/H4b ( Grades: 9-12 ): Nuclear weapons and energy remain matters of public concern and controversy.
10G/H5 ( Grades: 9-12 ): Radioactivity has many uses other than generating energy, including in medicine, industry, and scientific research in many different fields.
10J/M1 ( Grades: 6-8 ): In the 1800s, new machinery and steam engines to drive them made it possible to manufacture goods in factories, using fuels as a source of energy. In the factory system, workers, materials, and energy could be brought together efficiently.
11C/H10 ( Grades: 9-12 ): Whatever happens within a system, such as parts exploding, decaying, or reorganizing, some features, such as the total amount of matter and energy, remain precisely the same.
12C/M3 ( Grades: 6-8 ): Make accurate measurements of length, volume, weight, elapsed time, rates, and temperature by using appropriate devices.
4A/H2cd ( Grades: 9-12 ): Stars condensed by gravity out of clouds of molecules of the lightest elements until nuclear fusion of the light elements into heavier ones began to occur. Fusion released great amounts of energy over millions of years.
4B/E3 ( Grades: 3-5 ): When liquid water disappears, it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets or frozen crystals of water.
4B/H6 ( Grades: 9-12 ): The earth's climates have changed in the past, are currently changing, and are expected to change in the future, primarily due to changes in the amount of light reaching places on the earth and the composition of the atmosphere. The burning of fossil fuels in the last century has increased the amount of greenhouse gases in the atmosphere, which has contributed to Earth's warming.
4B/H8 ( Grades: 9-12 ): The earth has many natural resources of great importance to human life. Some are readily renewable, some are renewable only at great cost, and some are not renewable at all.
4B/M10ab ( Grades: 6-8 ): Some material resources are very rare and some exist in great quantities. The ability to obtain and process resources depends on where they are located and the form they are in. As resources are depleted, they may become more difficult to obtain.
4B/M11a ( Grades: 6-8 ): The wasteful or unnecessary use of natural resources can limit their availability for other purposes. Restoring depleted soil, forests, or fishing grounds can be difficult and costly.
4B/M11bc ( Grades: 6-8 ): The benefits of Earth's resources—such as fresh water, air, soil, and trees—can be reduced by deliberately or inadvertently polluting them. The atmosphere, the oceans, and the land have a limited capacity to absorb and recycle waste materials. In addition, some materials take a long time to degrade. Therefore, cleaning up polluted air, water, or soil can be difficult and costly.
4D/E1 ( Grades: 3-5 ): Heating and cooling can cause changes in the properties of materials, but not all materials respond the same way to being heated and cooled.
4D/H4 ( Grades: 9-12 ): The nucleus of radioactive isotopes is unstable and spontaneously decays, emitting particles and/or wavelike radiation. It cannot be predicted exactly when, if ever, an unstable nucleus will decay, but a large group of identical nuclei decay at a predictable rate. This predictability of decay rate allows radioactivity to be used for estimating the age of materials that contain radioactive substances.
4D/M3ab ( Grades: 6-8 ): Atoms and molecules are perpetually in motion. Increased temperature means greater average energy of motion, so most substances expand when heated.
4E/E2a ( Grades: 3-5 ): When warmer things are put with cooler ones, the warmer things get cooler and the cooler things get warmer until they all are the same temperature.
4E/H1 ( Grades: 9-12 ): Although the various forms of energy appear very different, each can be measured in a way that makes it possible to keep track of how much of one form is converted into another. Whenever the amount of energy in one place diminishes, the amount in other places or forms increases by the same amount.
4E/H10 ( Grades: 9-12 ): If no energy is transferred into or out of a system, the total energy of all the different forms in the system will not change, no matter what gradual or violent changes actually occur within the system.
4E/H2 ( Grades: 9-12 ): In any system of atoms or molecules, the statistical odds are that the atoms or molecules will end up with less order than they originally had and that the thermal energy will be spread out more evenly. The amount of order in a system may stay the same or increase, but only if the surrounding environment becomes even less ordered. The total amount of order in the universe always tends to decrease.
4E/H3 ( Grades: 9-12 ): As energy spreads out, whether by conduction, convection, or radiation, the total amount of energy stays the same. However, since it is spread out, less can be done with it.
4E/H6 ( Grades: 9-12 ): Energy is released whenever the nuclei of very heavy atoms, such as uranium or plutonium, split into middleweight ones, or when very light nuclei, such as those of hydrogen and helium, combine into heavier ones. For a given quantity of a substance, the energy released in a nuclear reaction is very much greater than the energy given off in a chemical reaction.
4E/H7 ( Grades: 9-12 ): Thermal energy in a system is associated with the disordered motions of its atoms or molecules. Gravitational energy is associated with the separation of mutually attracting masses. Electrical potential energy is associated with the separation of mutually attracting or repelling charges.
4E/H9 ( Grades: 9-12 ): Many forms of energy can be considered to be either kinetic energy, which is the energy of motion, or potential energy, which depends on the separation between mutually attracting or repelling objects.
4E/M4 ( Grades: 6-8 ): Energy appears in different forms and can be transformed within a system. Motion energy is associated with the speed of an object. Thermal energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching or compressing of an elastic object. Chemical energy is associated with the composition of a substance. Electrical energy is associated with an electric current in a circuit. Light energy is associated with the frequency of electromagnetic waves.
4F/M1 ( Grades: 6-8 ): Light from the sun is made up of a mixture of many different colors of light, even though to the eye the light looks almost white. Other things that give off or reflect light have a different mix of colors.
4F/M4 ( Grades: 6-8 ): Vibrations in materials set up wavelike disturbances that spread away from the source. Sound and earthquake waves are examples. These and other waves move at different speeds in different materials.
4G/H5ab ( Grades: 9-12 ): Magnetic forces are very closely related to electric forces and are thought of as different aspects of a single electromagnetic force. Moving electrically charged objects produces magnetic forces and moving magnets produces electric forces.
4G/H5c ( Grades: 9-12 ): The interplay of electric and magnetic forces is the basis for many modern technologies, including electric motors, generators, and devices that produce or receive electromagnetic waves.
4G/H6 ( Grades: 9-12 ): The nuclear forces that hold the protons and neutrons in the nucleus of an atom together are much stronger than the electric forces between the protons and electrons of the atom. That is why much greater amounts of energy are released from nuclear reactions than from chemical reactions.
4G/H7 ( Grades: 9-12 ): Electric currents in the earth's interior give the earth an extensive magnetic field, which we detect from the orientation of compass needles.
5E/E2 ( Grades: 3-5 ): Some source of "energy" is needed for all organisms to stay alive and grow.
5E/M3c ( Grades: 6-8 ): Almost all food energy comes originally from sunlight.
7G/M5 ( Grades: 6-8 ): The global environment is affected by national and international policies and practices relating to energy use, waste disposal, ecological management, manufacturing, and population.
8B/H7 ( Grades: 9-12 ): The development of new materials and the increased use of existing materials by a growing human population have led to the removal of resources from the environment much more rapidly than they can be replaced by natural processes. Disposal of waste materials has also become a problem. Solving these problems requires systematic efforts involving both social and technological innovations.
8C/E4 ( Grades: 3-5 ): Some people try to reduce the amount of fuels they use in order to conserve resources, reduce pollution, or save money.
8C/H2 ( Grades: 9-12 ): When selecting fuels, it is important to consider the relative advantages and disadvantages of each fuel.
8C/H3 ( Grades: 9-12 ): Nuclear reactions release energy without the combustion products of burning fuels, but the radioactivity of fuels and their by-products poses other risks.
8C/H4 ( Grades: 9-12 ): Industrialization brings an increased demand for and use of energy. Such usage contributes to having many more goods and services in the industrially developing nations but also leads to more rapid depletion of the earth's energy resources and to environmental risks associated with some energy resources.
8C/H6 ( Grades: 9-12 ): The useful energy output of a device—that is, what energy is available for further change—is always less than the energy input, with the difference usually appearing as thermal energy. One goal in the design of such devices is to make them as efficient as possible—that is, to maximize the useful output for a given input.
8C/H7 ( Grades: 9-12 ): During any transformation of energy, there is inevitably some dissipation of energy into the environment. In this practical sense, energy gets "used up," even though it is still around somewhere.
8C/H8 ( Grades: 9-12 ): Sunlight is the ultimate source of most of the energy we use. The energy in fossil fuels such as oil and coal comes from energy that plants captured from the sun long ago.
8C/M1 ( Grades: 6-8 ): Transformations and transfers of energy within a system usually result in some energy escaping into its surrounding environment. Some systems transfer less energy to their environment than others during these transformations and transfers.
8C/M10 ( Grades: 6-8 ): Some resources are not renewable or renew very slowly. Fuels already accumulated in the earth, for instance, will become more difficult to obtain as the most readily available resources run out. How long the resources will last, however, is difficult to predict. The ultimate limit may be the prohibitive cost of obtaining them.
8C/M11 ( Grades: 6-8 ): By burning fuels, people are releasing large amounts of carbon dioxide into the atmosphere and transforming chemical energy into thermal energy which spreads throughout the environment.
8C/M3 ( Grades: 6-8 ): In many instances, manufacturing and other technological activities are performed at a site close to an energy resource. Some forms of energy are transported easily, others are not.
8C/M4 ( Grades: 6-8 ): Electrical energy can be generated from a variety of energy resources and can be transformed into almost any other form of energy. Electric circuits are used to distribute energy quickly and conveniently to distant locations.
8C/M6 ( Grades: 6-8 ): Industry, transportation, urban development, agriculture, and most other human activities are closely tied to the amount and kind of energy available. People in different parts of the world have different amounts and kinds of energy resources to use and use them for different purposes.
8C/M7 ( Grades: 6-8 ): # Energy is required for technological processes such as taking apart, putting together, moving around, and communicating.
8C/M8 ( Grades: 6-8 ): People have invented ingenious ways of deliberately bringing about energy transformations that are useful to them.
8C/M9 ( Grades: 6-8 ): Energy resources are more useful if they are concentrated and easy to transport.
8D/M2 ( Grades: 6-8 ): Information can be carried by many media, including sound, light, and objects. In the 1900s, the ability to code information as electric currents in wires, electromagnetic waves in space, and light in glass fibers has made communication millions of times faster than mail or sound.
NSTA National Science Education Standards
B.1.4 ( Grades: 9-12 ): Radioactive isotopes are unstable and undergo spontaneous nuclear reactions, emitting particles and/or wavelike radiation. The decay of any one nucleus cannot be predicted, but a large group of identical nuclei decay at a predictable rate. This predictability can be used to estimate the age of materials that contain radioactive isotopes.
B.3.6 ( Grades: 5-8 ): The sun is a major source of energy for changes on the earth's surface. The sun loses energy by emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. The sun's energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation.
B.5.2 ( Grades: 9-12 ): 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.
C.5.1 ( Grades: 9-12 ): All matter tends toward more disorganized states. Living systems require a continuous input of energy to maintain their chemical and physical organizations. With death, and the cessation of energy input, living systems rapidly disintegrate.
D.1.1 ( Grades: 9-12 ): Earth systems have internal and external sources of energy, both of which create heat. The sun is the major external source of energy. Two primary sources of internal energy are the decay of radioactive isotopes and the gravitational energy from the earth's original formation.
D.1.2 ( Grades: 9-12 ): 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.
F.2.2 ( Grades: 5-8 ): Causes of environmental degradation and resource depletion vary from region to region and from country to country.
F.3.1 ( Grades: 9-12 ): 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.
F.3.2 ( Grades: 9-12 ): 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.