Following the vision of A Framework for K–12 Science Education (Framework), the Next Generation Science Standards (NGSS) are intended to increase coherence in K–12 science education. The following excerpt from the Framework explains the approach in more detail:
First, it is built on the notion of learning as a developmental progression. It is designed to help children continually build on and revise their knowledge and abilities, starting from their curiosity about what they see around them and their initial conceptions about how the world works. The goal is to guide their knowledge toward a more scientifically based and coherent view of the natural sciences and engineering, as well as of the ways in which they are pursued and their results can be used.
Second, the framework focuses on a limited number of core ideas in science and engineering both within and across the disciplines. The committee made this choice in order to avoid the shallow coverage of a large number of topics and to allow more time for teachers and students to explore each idea in greater depth. Reduction of the sheer sum of details to be mastered is intended to give time for students to engage in scientific investigations and argumentation and to achieve depth of understanding of the core ideas presented. Delimiting what is to be learned about each core idea within each grade band also helps clarify what is most important to spend time on, and avoid the proliferation of detail to be learned with no conceptual grounding.
Third, the framework emphasizes that learning about science and engineering involves integration of the knowledge of scientific explanations (i.e., content knowledge) and the practices needed to engage in scientific inquiry and engineering design. Thus the framework seeks to illustrate how knowledge and practice must be intertwined in designing learning experiences in K–12 science education. (NRC, 2012)
DISCIPLINARY CORE IDEA PROGRESSION
The Framework describes the progression of disciplinary core ideas in the grade-band endpoints. The progressions are summarized in this section of the NGSS appendixes, which describe the content that occurs at each grade band. Some of the sub-ideas within the disciplinary core ideas overlap significantly. Readers will notice there is not always a clear division between those ideas, so several progressions are divided among more than one sub-idea. The purpose of these diagrams is to briefly describe the content at each grade band for each disciplinary core idea across K–12. This progression is for reference only. The full progressions can be seen in the Framework. In addition, the NGSS show the integration of the three dimensions. This document in no way endorses separating the disciplinary core ideas from the other two dimensions.
NRC (National Research Council). (2012). A framework for K–12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: The National Academies Press.
|PS1.A Structure of matter (includes PS1.C Nuclear processes)||Matter exists as different substances that have observable different properties. Different properties are suited to different purposes. Objects can be built up from smaller parts.||Matter exists as particles that are too small to see, and so matter is always conserved even if it seems to disappear. Measurements of a variety of observable properties can be used to identify particular materials.||The fact that matter is composed of atoms and molecules can be used to explain the properties of substances, diversity of materials, states of matter, phase changes, and conservation of matter.||The sub-atomic structural model and interactions between electrical charges at the atomic scale can be used to explain the structure and interactions of matter, including chemical reactions and nuclear processes. Repeating patterns of the periodic table reflect patterns of outer electrons. A stable molecule has less energy than the same set of atoms separated; one must provide at least this energy to take the molecule apart.|
|PS1.B Chemical reactions||Heating and cooling of substances cause changes that are sometimes reversible and sometimes not.||Chemical reactions that occur when substances are mixed can be identified by the emergence of substances with different properties; the total mass remains the same.||Reacting substances rearrange to form different molecules, but the number of atoms is conserved. Some reactions release energy and others absorb energy.||Chemical processes are understood in terms of collisions of molecules, rearrangement of atoms, and changes in energy as determined by properties of the elements involved.|
|PS2.A Forces and motion||Pushes and pulls can have different strengths and directions, and can change the speed or direction of an object’s motion or start or stop it.||The effect of unbalanced forces on an object results in a change of motion. Patterns of motion can be used to predict future motion. Some forces act through contact; some forces act even when the objects are not in contact. The gravitational force of Earth acting on an object near Earth’s surface pulls that object toward the planet’s center.||The role of the mass of an object must be qualitatively accounted for in any change of motion due to the application of a force.||Newton’s Second Law of Motion (F = ma) and the conservation of momentum can be used to predict changes in the motion of macroscopic objects.|
|PS2.B Types of interactions||Forces that act at a distance involve fields that can be mapped by their relative strength and effect on an object.||Forces at a distance are explained by fields that can transfer energy and that can be described in terms of the arrangement and properties of the interacting objects and the distance between them. These forces can be used to describe the relationship between electrical and magnetic fields.|
|PS2.C Stability and instability in physical systems||N/A||N/A||N/A||N/A|
|PS3.A Definitions of energy||N/A||Moving objects contain energy. The faster an object moves, the more energy it has. Energy can be moved from place to place by moving objects or through sound, light, or electrical currents. Energy can be converted from one form to another.||Kinetic energy can be distinguished from the various forms of potential energy. Energy changes to and from each type can be tracked through physical or chemical interactions. The relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter.||The total energy within a system is conserved. Energy transfer within and between systems can be described and predicted in terms of the energy associated with the motion or configuration of particles (objects).
Systems move toward stable states.
|PS3.B Conservation of energy and energy transfer||[Content found in PS3.D]|
|PS3.C Relationship between energy and forces||Bigger pushes and pulls cause bigger changes in an object’s motion or shape.||When objects collide, contact forces transfer energy so as to change the objects’ motions.||When two objects interact, each exerts a force on the other, and these forces can transfer energy between them.||A field contains energy that depends on the arrangement of the objects in the field.|
|PS3.D Energy in chemical processes and everyday life||Sunlight warms Earth’s surface.||Energy can be “produced,” “used,” or “released” by converting stored energy. Plants capture energy from sunlight, which can later be used as fuel or food.||Sunlight is captured by plants and used in a reaction to produce sugar molecules, which can be reversed by burning those molecules to release energy.||Photosynthesis is the primary biological means of capturing radiation from the sun. Energy cannot be destroyed; it can be converted to less useful forms.|
|PS4.A Wave properties||Sound can make matter vibrate, and vibrating matter can make sound.||Waves are regular patterns of motion, which can be made in water by disturbing the surface. Waves of the same type can differ in amplitude and wavelength. Waves can make objects move.||A simple wave model has a repeating pattern with a specific wavelength, frequency, and amplitude, and mechanical waves need a medium through which they are transmitted. This model can explain many phenomena, including sound and light. Waves can transmit energy.||The wavelength and frequency of a wave are related to one another by the speed of the wave, which depends on the type of wave and the medium through which it is passing. Waves can be used to transmit information and energy.|
|PS4.B Electromagnetic radiation||Objects can be seen only when light is available to illuminate them.||An object can be seen when light reflected from its surface enters our eyes.
Patterns can encode, send, receive, and decode information.
|The construct of a wave is used to model how light interacts with objects.||Both an electromagnetic wave model and a photon model explain features of electromagnetic radiation broadly and describe common applications of electromagnetic radiation.|
|PS4.C Information technologies and instrumentation||People use devices to send and receive information.||Waves can be used to transmit digital information. Digitized information is comprised of a pattern of ones and zeros.||Large amounts of information can be stored and shipped around as a result of being digitized.|
|LS1.A Structure and function||All organisms have external parts that they use to perform daily functions.||Organisms have both internal and external macroscopic structures that allow for growth, survival, behavior, and reproduction.||All living things are made up of cells. In organisms, cells work together to form tissues and organs that are specialized for particular body functions.||Systems of specialized cells within organisms help perform essential functions of life. Any one system in an organism is made up of numerous parts. Feedback mechanisms maintain an organism’s internal conditions within certain limits and mediate behaviors.|
|LS1.B Growth and development of organisms||Parents and offspring often engage in behaviors that help the offspring survive.||Reproduction is essential to every kind of organism. Organisms have unique and diverse life cycles.||Animals engage in behaviors that increase the odds of reproduction. An organism’s growth is affected by both genetic and environmental factors.||Growth and division of cells in organisms occur by mitosis and differentiation for specific cell types.|
|LS1.C Organization for matter and energy flow in organisms||Animals obtain food they need from plants or other animals. Plants need water and light.||Food provides animals with the materials and energy they need for body repair, growth, warmth, and motion. Plants acquire material for growth chiefly from air, water, and process matter and obtain energy from sunlight, which is used to maintain conditions necessary for survival.||Plants use the energy from light to make sugars through photosynthesis. Within individual organisms, food is broken down through a series of chemical reactions that rearrange molecules and release energy.||The hydrocarbon backbones of sugars produced through photosynthesis are used to make amino acids and other molecules that can be assembled into proteins or DNA. Through cellular respiration, matter and energy flow through different organizational levels of an organism as elements are recombined to form different products and transfer energy.|
|LS1.D Information processing||Animals sense and communicate information and respond to inputs with behaviors that help them grow and survive.||Different sense receptors are specialized for particular kinds of information; animals use their perceptions and memories to guide their actions.||Each sense receptor responds to different inputs, transmitting them as signals that travel along nerve cells to the brain; the signals are then processed in the brain, resulting in immediate behavior or memories.||N/A|
|LS2.A Interdependent relationships in ecosystems||Plants depend on water and light to grow and on animals for pollination or to move their seeds around.||The food of almost any animal can be traced back to plants. Organisms are related in food webs in which some animals eat plants for food and other animals eat the animals that eat plants, while decomposers restore some materials to the soil.||Organisms and populations are dependent on their environmental interactions with both other living things and non-living factors, any of which can limit their growth. Competitive, predatory, and mutually beneficial interactions vary across ecosystems, but the patterns are shared.||Ecosystems have carrying capacities resulting from biotic and abiotic factors. The fundamental tension between resource availability and organism populations affects the abundance of species in any given ecosystem.|
|LS2.B Cycles of matter and energy transfer in ecosystems||[Content found in LS1.C and ESS3.A]||Matter cycles between the air and soil and among organisms as they live and die.||The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and non-living parts of the ecosystem. Food webs model how matter and energy are transferred among producers, consumers, and decomposers as the three groups interact within an ecosystem.||Photosynthesis and cellular respiration provide most of the energy for life processes. Only a fraction of matter consumed at the lower level of a food web is transferred up, resulting in fewer organisms at higher levels. At each link in an ecosystem elements are combined in different ways and matter and energy are conserved. Photosynthesis and cellular respiration are key components of the global carbon cycle.|
|LS2.C Ecosystem dynamics, functioning, and resilience||N/A||When the environment changes some organisms survive and reproduce, some move to new locations, some move into the transformed environment, and some die.||Ecosystem characteristics vary over time. Disruptions to any part of an ecosystem can lead to shifts in all of its populations. The completeness or integrity of an ecosystem’s biodiversity is often used as a measure of its health.||If a biological or physical disturbance to an ecosystem occurs, including one induced by human activity, the ecosystem may return to its more or less original state or become a very different ecosystem, depending on the complex set of interactions within the ecosystem.|
|LS2.D Social interactions and group behavior||N/A||Being part of a group helps animals obtain food, defend themselves, and cope with changes.||N/A||Group behavior has evolved because membership can increase the chances of survival for individuals and their genetic relatives.|
|LS3.A Inheritance of traits||Young organisms are very much, but not exactly, like their parents and also resemble other organisms of the same kind.||Different organisms vary in how they look and function because they have different inherited information; the environment also affects the traits that an organism develops.||Genes chiefly regulate specific proteins, which affect an individual’s traits.||DNA carries instructions for forming species’ characteristics. Each cell in an organism has the same genetic content, but genes expressed by cells can differ.|
|LS3.B Variation of traits||In sexual reproduction each parent contributes half the genes acquired by the offspring, resulting in variation between parent and offspring. Genetic information can be altered because of mutations, which may result in beneficial, negative, or no change to proteins in or traits of an organism.||The variation and distribution of traits in a population depend on genetic and environmental factors. Genetic variation can result from mutations caused by environmental factors or errors in DNA replication or from chromosomes swapping sections during meiosis.|
|LS4.A Evidence of common ancestry and diversity||N/A||Some living organisms resemble organisms that once lived on Earth. Fossils provide evidence about the types of organisms and environments that existed long ago.||The fossil record documents the existence, diversity, extinction, and change of many life forms and their environments through Earth’s history. The fossil record and comparisons of anatomical similarities between organisms enable the inference of lines of evolutionary descent.||The ongoing branching that produces multiple lines of descent can be inferred by comparing DNA sequences, amino acid sequences, and anatomical and embryological evidence of different organisms.|
|LS4.B Natural selection||N/A||Differences in characteristics between individuals of the same species provide advantages in survival and reproduction.||Both natural and artificial selection result from certain traits giving some individuals an advantage in survival and reproduction, leading to predominance of certain traits in a population.||Natural selection occurs only if there is variation in the genes and traits of organisms in a population. Traits that positively affect survival can become more common in a population.|
|LS4.C Adaptation||N/A||Particular organisms can survive only in particular environments.
Populations of organisms live in a variety of habitats. Change in those habitats affects the organisms living there.
|Species can change over time in response to changes in environmental conditions through adaptation by natural selection acting over generations. Traits that support successful survival and reproduction in the new environment become more common.||Evolution results primarily from genetic variation of individuals in a species, competition for resources, and proliferation of organisms better able to survive and reproduce. Adaptation means that the distribution of traits in a population, as well as species’ expansion, emergence, or extinction, can change when conditions change.|
|LS4.D Biodiversity and humans||A range of different organisms lives in different places.||Changes in biodiversity can influence humans’ resources and the ecosystem services they rely on.||Biodiversity is increased by the formation of new species and reduced by extinction. Humans depend on biodiversity but also have adverse impacts on it. Sustaining biodiversity is essential to supporting life on Earth.|
|ESS1.A The universe and its stars||Patterns of movement of the sun, moon, and stars as seen from Earth can be observed, described, and predicted.||Stars range greatly in size and distance from Earth, and this can explain their relative brightness.
The solar system is part of the Milky Way, which is one of many billions of galaxies.
|Light spectra from stars are used to determine their characteristics, processes, and life cycles. Solar activity creates the elements through nuclear fusion. The development of technologies has provided astronomical data that provide empirical evidence for the Big Bang theory.|
|ESS1.B Earth and the solar system||Earth’s orbit and rotation and the orbit of the moon around Earth cause observable patterns.||The solar system contains many varied objects held together by gravity. Solar system models explain and predict eclipses, lunar phases, and seasons.||Kepler’s Laws describe common features of the motions of orbiting objects. Observations from astronomy and space probes provide evidence for explanations of solar system formation. Changes in Earth’s tilt and orbit cause climate changes such as ice ages.|
|ESS1.C The history of planet Earth||Some events on Earth occur very quickly; others can occur very slowly.||Certain features on Earth can be used to order events that have occurred in a landscape.||Rock strata and the fossil record can be used as evidence to organize the relative occurrence of major historical events in Earth’s history.||The rock record resulting from tectonic and other geoscience processes as well as objects from the solar system can provide evidence of Earth’s early history and the relative ages of major geologic formations.|
|ESS2.A Earth’s materials and systems||Wind and water change the shape of the land.||Four major Earth systems interact. Rainfall helps to shape the land and affects the types of living things found in a region. Water, ice, wind, organisms, and gravity break rocks, soils, and sediments into smaller pieces and move them around.||Energy flows and matter cycles within and among Earth’s systems, including the sun and Earth’s interior as primary energy sources. Plate tectonics is one result of these processes.||Feedback effects exist within and among Earth’s systems.|
|ESS2.B Plate tectonics and large-scale system interactions||Maps show where things are located. The shapes and kinds of land and water in any area can be mapped.||Earth’s physical features occur in patterns, as do earthquakes and volcanoes. Maps can be used to locate features and determine patterns in those events.||Plate tectonics is the unifying theory that explains the movements of rocks at Earth’s surface and geologic history. Maps are used to display evidence of plate movement.||Radioactive decay within Earth’s interior contributes to thermal convection in the mantle.|
|ESS2.C The roles of water in Earth’s surface processes||Water is found in many types of places and in different forms on Earth.||Most of Earth’s water is in the ocean and much of Earth’s fresh water is in glaciers or underground.||Water cycles among land, ocean, and atmosphere and is propelled by sunlight and gravity. Density variations of sea water drive interconnected ocean currents. Water movement causes weathering and erosion, changing landscape features.
Complex interactions determine local weather patterns and influence climate, including the role of the ocean.
|The planet’s dynamics are greatly influenced by water’s unique chemical and physical properties.|
|ESS2.D Weather and climate||Weather is the combination of sunlight, wind, snow or rain, and temperature in a particular region and time. People record weather patterns over time.||Climate describes patterns of typical weather conditions over different scales and variations. Historical weather patterns can be analyzed.||The role of radiation from the sun and its interactions with the atmosphere, ocean, and land are the foundation for the global climate system. Global climate models are used to predict future changes, including changes influenced by human behavior and natural factors.|
|ESS2.E Biogeology||Plants and animals can change their local environment.
Living things need water, air, and resources from the land, and they live in places that have the things they need. Humans use natural resources for everything they do.
|Living things can affect the physical characteristics of their environment.||[Content found in LS4.A and LS4.D]||The biosphere and Earth’s other systems have many interconnections that cause a continual co-evolution of Earth’s surface and life on it|
|ESS3.A Natural resources||Energy and fuels that humans use are derived from natural sources and their use affects the environment. Some resources are renewable over time, others are not.||Humans depend on Earth’s land, ocean, atmosphere, and biosphere for different resources, many of which are limited or not renewable. Resources are distributed unevenly around the planet as a result of past geologic processes.||Resource availability has guided the development of human society and the use of natural resources has associated costs, risks, and benefits.|
|ESS3.B Natural hazards||In a region some kinds of severe weather are more likely than others. Forecasts allow communities to prepare for severe weather.||A variety of hazards result from natural processes; humans cannot eliminate hazards but can reduce their impacts.||Some natural hazards can be predicted by mapping the history of those natural hazards in a region and understanding related geologic forces.||Natural hazards and other geologic events have shaped the course of human history at local, regional, and global scales.|
|ESS3.C Human impacts on Earth systems||Things people do can affect the environment, but they can make choices to reduce their impacts.||Societal activities have had major effects on land, ocean, atmosphere, and even outer space. Societal activities can also help protect Earth’s resources and environments.||Human activities have altered the biosphere, sometimes damaging it, although changes to environments can have different impacts for different living things. Activities and technologies can be engineered to reduce people’s impacts on Earth.||Sustainability of human societies and of the biodiversity that supports them requires responsible management of natural resources, including the development of technologies.|
|ESS3.D Global climate change||N/A||N/A||Human activities affect global warming. Decisions to reduce the impact of global warming depend on understanding climate science, engineering capabilities, and social dynamics.||Global climate models used to predict changes continue to be improved, although discoveries about the global climate system are ongoing and continually needed.|