Earth and Space Science.

1. (1) Earth’s Place in the Universe.
2. (A) Performance expectation 1. Develop a model based on evidence to illustrate the life span of the Sun, and the role of nuclear fusion in the Sun’s core to convert matter to energy that eventually reaches Earth in the form of radiation.
3. (i) Clarification Statement. Emphasis is on the energy transfer mechanisms that allow energy from nuclear fusion in the Sun’s core to reach Earth. Examples of evidence for the model could include observations of the masses and lifetimes of other stars, how the Sun’s radiation varies due to sudden solar flares (“space weather”), the 11-year sunspot cycle, sunspots, solar emission spectra, previous studies of nuclear fusion experiments on Earth (colliders), and non-cyclic variations over centuries.
4. (ii) Assessment Boundary. Assessment does not include details of the atomic and subatomic processes involved with the Sun’s nuclear fusion.
5. (iii) Science and Engineering Practices. Develop and Use Models. Develop and/or use a model (including mathematical and computational) to generate data to support explanations, predict phenomena, analyze systems, and/or solve problems.
6. (iv) Disciplinary Core Ideas.
7. (I) The Universe and Its Stars. The star called the Sun is changing and will burn out over a lifespan of approximately 10 billion years.
8. (II) Energy in Chemical Processes and Everyday Life. Nuclear fusion processes in the center of the Sun release the energy that ultimately reaches Earth as radiation.
9. (v) Crosscutting Concepts. Energy and Matter. Changes of energy and matter in a system can be described in terms of energy and matter flows into, out of, and within that system.
10. (B) Performance expectation 2. Construct an explanation of how the universe formed as a single point and continues to expand based on astronomical evidence of light spectra, motion of distant galaxies, and the composition of matter in the universe.
11. (i) Clarification Statement. Emphasis is on the astronomical evidence supporting the expansion of the universe, including the redshift of light from galaxies, the remnant cosmic microwave background radiation, and the composition of ordinary matter, primarily found in stars and interstellar gases.
12. (ii) Assessment Boundary. Details about the mapped distribution of galaxies and clusters are not assessed.
13. (iii) Science and Engineering Practices. Constructing Explanations. Use evidence (e.g., measurements, observations, patterns) to construct or support an explanation or design a solution to a problem.
14. (iv) Disciplinary Core Ideas. The Universe and Its Stars.
15. (I) The study of stars’ light spectra and brightness is used to identify compositional elements of stars, their movements, and their distances from Earth.
16. (II) Observations of distant galaxies receding from our own, the measured composition of stars and non-stellar gases, and maps of spectra of the primordial radiation (cosmic microwave background) that still fills the universe are used as evidence to support the explanation of formation.
17. (v) Crosscutting Concepts. Scale, Proportion, & Quantity. Some systems can only be studied indirectly as they are too small, too large, too fast, or too slow to observe directly.
18. (vi) Connections to Scientific Literacy.
19. (I) Science Models, Laws, and Theories Explain Natural Phenomena. A scientific theory is a substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment and the science community validates each theory before it is accepted. If new evidence is discovered that the theory does not accommodate, the theory is generally modified in light of this new evidence.
20. (II) Scientific Knowledge Assumes an Order and Consistency in Natural Systems. Scientific knowledge is based on the assumption that natural laws operate today as they did in the past and they will continue to do so in the future. Science assumes the universe is a vast single system in which basic laws are consistent.
21. (C) Performance expectation 3. Construct an explanation about the process that causes stars to produce elements throughout their life cycle.
22. (i) Clarification Statement. Emphasis is on the way the different elements formed, depending on the mass of a star and the stage of its life. Evidence could include stellar spectra, models of nucleosynthesis, and observations of stars of different ages and masses (e.g., H-R diagrams and stellar classification).
23. (ii) Assessment Boundary. Details of the many different nucleosynthesis pathways for stars of different masses are not assessed.
24. (iii) Science and Engineering Practices. Constructing Explanations.Use evidence (e.g., measurements, observations, patterns) to construct or support an explanation.
25. (iv) Disciplinary Core Ideas.
26. (I) The Universe and Its Stars.

a. The study of stars’ light spectra and brightness is used to identify compositional elements of stars, their movements, and their distances from Earth.

b. Other than the hydrogen and helium formed at the time of formation, nuclear fusion within stars produces all atomic nuclei lighter than and including iron, and the process releases electromagnetic energy.

c. Heavier elements are produced when certain massive stars achieve a supernova stage and explode.

1. (II) Electromagnetic Radiation. Atoms of each element emit and absorb characteristic frequencies of light. These characteristics allow identification of the presence of an element, even in microscopic quantities.
2. (v) Crosscutting Concepts. Cause and Effect. Empirical evidence is required to differentiate between cause and correlation and make claims about specific causes and effects.
3. (D) Performance expectation 4. Use models to determine patterns that can be used to predict the motion of orbiting objects in the Solar System.
4. (i) Clarification Statement. Emphasis is on Newtonian gravitational laws governing orbital motions, which apply to human-made satellites as well as planets, moons, and exoplanets. Models could include graphical representations of orbits.
5. (ii) Assessment Boundary. Mathematical representations for the gravitational attraction of bodies and Kepler’s Laws of Orbital Motions should not deal with more than two bodies, nor involve calculus.
6. (iii) Science and Engineering Practices. Developing and Using Models. Develop and/or use a model (including mathematical and computational) to generate data to support explanations, predict phenomena, analyze systems, and/or solve problems.
7. (iv) Disciplinary Core Ideas.
8. (I) The Universe and Its Stars. The study of stars' light spectra and brightness is used to identify compositional elements of stars, their movements, and their distances from Earth.
9. (II) Earth and the Solar System.

a. The solar system consists of the Sun and a collection of objects of varying sizes and conditions-including planets and their moons-that are held in orbit around the Sun by its gravitational pull on them.

b. Kepler’s laws describe common features of the motions of orbiting objects, including their elliptical paths around the Sun. Orbits may change due to the gravitational effects from, or collisions with, other objects in the solar system.

1. (III) Interdependence of Science, Engineering, and Technology. Science and engineering complement each other in the cycle known as research and development (R&D). Many R&D projects may involve scientists, engineers, and others with wide ranges of expertise.
2. (v) Crosscutting Concepts. Patterns. Mathematical representations are needed to identify some patterns.
3. (E) Performance expectation 5. Evaluate patterns in evidence of the past and current movements of continental and oceanic crust and the theory of plate tectonics to explain the ages of crustal rocks.
4. (i) Clarification Statement. Emphasis is on the ability of plate tectonics to explain the ages of crustal rocks. Examples could include evidence of the ages of oceanic crust increasing with distance from mid-ocean ridges (a result of plate spreading) and the ages of North American continental crust decreases with distance away from a central ancient core (a result of past plate interactions), the existence of past supercontinents, and data from paleomagnetism.
5. (ii) Science and Engineering Practices. Engaging in Argument from Evidence. Evaluate the claims, evidence, and/or reasoning behind currently accepted explanations or solutions to determine the merit of arguments.
6. (iii) Disciplinary Core Ideas.
7. (I) The History of Planet Earth. Continental rocks are generally much older than the rocks of the ocean floor.
8. (II) Plate Tectonics and Large-Scale System Interactions. Plate tectonics is the unifying theory that explains the past and current movements of the rocks at Earth’s surface and provides a framework for understanding its geologic history.
9. (III) Nuclear Processes. Spontaneous radioactive decay follows a characteristic exponential decay law. Nuclear lifetimes allow radiometric dating to be used to determine the ages of rocks and other materials.
10. (iv) Crosscutting Concepts. Stability and Change. Much of science deals with constructing explanations of how things change and how they remain stable.
11. (F) Performance expectation 6. Apply scientific reasoning and evidence from ancient Earth materials, meteorites, and other planetary surfaces to construct an account of changes in Earth’s formation and early history.
12. (i) Clarification Statement. Emphasis is on using available evidence within the Solar System to reconstruct the early history of Earth, which formed along with the rest of the Solar System as described by the solar nebular theory. Examples of evidence could include the absolute ages of ancient materials (obtained by radiometric dating of meteorites, Moon rocks, Earth’s oldest minerals), the sizes and compositions of solar system objects, and the impact cratering record of planetary surfaces.
13. (ii) Science and Engineering Practices. Constructing Explanations. Apply scientific reasoning, theory, and/or models to link evidence to the claims to assess the extent to which the reasoning and data support the explanation or conclusion.
14. (iii) Disciplinary Core Ideas.
15. (I) The History of Planet Earth. Although active geologic processes, such as plate tectonics and erosion, have destroyed or altered most of the very early rock record on Earth, other objects in the solar system, such as lunar rocks, asteroids, and meteorites, have changed little over billions of years. Studying these objects can provide information about Earth’s formation and early history.
16. (II) Nuclear Processes. Spontaneous radioactive decay follows a characteristic exponential decay law. Nuclear lifetimes allow radiometric dating to be used to determine the ages of rocks and other materials.
17. (iv) Crosscutting Concepts. Stability and Change. Much of science deals with constructing explanations of how things change and how they remain stable.
18. (v) Connections to Scientific Literacy. Science Models, Laws, and Theories Explain Natural Phenomena. A scientific theory is a substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment and the science community validates each theory before it is accepted. If new evidence is discovered that the theory does not accommodate, the theory is generally modified in light of this new evidence. Models, mechanisms, and explanations collectively serve as tools in the development of a scientific theory.
19. (2) Earth Systems.
20. (A) Performance expectation 1. Develop a model to illustrate how Earth’s internal and surface processes operate at different scales of space and time to form continental and ocean-floor features.
21. (i) Clarification Statement. Emphasis is on how the appearance of land features (e.g., mountains, valleys, plateaus) and sea-floor features (e.g., trenches, ridges, seamounts) are a result of both constructive forces (e.g., volcanism, tectonic uplift, mountain building) and destructive mechanisms (e.g., such as weathering, erosion, and landslides or mudslides).
22. (ii) Assessment Boundary. Assessment does not include memorization of formation details of specific geographic features of Earth’s surface.
23. (iii) Science and Engineering Practices. Developing and Using Models. Develop a model based on evidence to illustrate the relationships between systems or components of a system.
24. (iv) Disciplinary Core Ideas.
25. (I) Earth Materials and Systems. Earth’s systems, being dynamic and interacting, cause feedback effects that can increase or decrease the original changes.
26. (II) Plate Tectonics and Large-Scale System Interactions.

a. Plate tectonics is the unifying theory that explains the past and current movements of rocks at Earth’s surface and provides a framework for understanding its geologic history.

b. Plate movements are responsible for most continental and ocean-floor features and for the distribution of most rocks and minerals within the Earth's crust.

1. (v) Crosscutting Concepts. Scale, Proportion, and Quantity. Some systems can only be studied indirectly as they are too small, too large, too fast, or too slow to observe directly.
2. (B) Performance expectation 2. Analyze geoscience data to make the claim that one change to Earth’s surface can create feedback and interactions that cause changes to other Earth systems.
3. (i) Clarification Statement. Examples could be taken from system interactions, such as how the loss of ground vegetation causes an increase in water runoff and soil erosion, which limits additional vegetation patterns; how dammed rivers increase groundwater recharge, decrease sediment transport, and increase coastal erosion; or how the loss of wetlands causes a decrease in local humidity that further reduces the wetland extent. Examples could also include climate feedbacks that increase surface temperatures through geologic time.
4. (ii) Science and Engineering Practices. Analyzing and Interpreting Data. Analyze data using tools, technologies, and/or models in order to make valid and reliable scientific claims.
5. (iii) Disciplinary Core Ideas.
6. (I) Earth Materials and Systems. Earth’s systems, being dynamic and interacting, cause feedback effects that can increase or decrease the original changes.
7. (II) Weather and Climate. The foundation for Earth’s global climate system is the electromagnetic radiation from the Sun, as well as its reflection, absorption, storage, and redistribution among the atmosphere, ocean, and land systems, and this energy’s re-radiation into space.
8. (iv) Crosscutting Concepts. Stability and Change. Feedback (negative or positive) can stabilize or destabilize a system.
9. (C) Performance expectation 3. Develop a model based on evidence of Earth’s interior to describe the cycling of matter by thermal convection.
10. (i) Clarification Statement. Emphasis is on both a one-dimensional model of Earth, with radial layers determined by density, and a three-dimensional model, which is controlled by mantle convection and the resulting plate tectonics. Examples of evidence could include maps of the Earth’s surface features; three-dimensional structure in the subsurface, obtained from seismic waves; records of the rate of change of Earth’s magnetic field (as constraints on convection in the outer core); and prediction of the composition of Earth’s layers from high pressure laboratory experiments.
11. (ii) Assessment Boundary. Emphasis is on the processes occurring in the layers of the Earth.
12. (iii) Science and Engineering Practices. Developing and Using Models. Develop a model based on evidence to illustrate the relationships between systems or components of a system.
13. (iv) Disciplinary Core Ideas.
14. (I) Earth Materials and Systems.

a. Evidence from deep probes and seismic waves, reconstructions of historical changes in Earth’s surface features, its magnetic field, and an understanding of physical and chemical processes lead to a model of Earth with a hot but solid inner core, a liquid outer core, a solid mantle and crust.

b. Motions of the mantle and its plates occur primarily through thermal convection, which involves the cycling of matter due to the outward flow of energy from Earth’s interior and gravitational movement of denser materials toward the interior.

1. (II) Plate Tectonics and Large-Scale System Interactions.

a. The radioactive decay of unstable isotopes continually generates new energy within Earth’s crust and mantle, providing the primary source of the heat that drives mantle convection.

b. Plate tectonics can be viewed as the surface expression of mantle convection.

1. (III) Wave Properties. Geologists use seismic waves and their reflection at interfaces between layers to probe structures deep in the planet.
2. (v) Crosscutting Concepts. Energy and Matter. Energy drives the cycling of matter within and between systems.
3. (vi) Connections to Scientific Literacy. Science Knowledge is Based on Empirical Evidence. Science disciplines share common rules of evidence used to evaluate explanations about natural systems. Science includes the process of coordinating patterns of evidence with current theory.
4. (D) Performance expectation 4. Analyze and interpret data to explore how variations in the flow of energy into and out of Earth’s systems cause changes to the atmosphere and climate.
5. (i) Clarification Statement. Changes occur over different timescales, from sudden (e.g., large volcanic eruptions, ocean circulation), to intermediate (e.g., ocean circulation, solar output, human activity), and long-term variations (e.g., Earth’s orbit, axis orientation, atmospheric composition). Human activities (e.g., fossil fuel combustion, cement production, and agriculture) and natural processes (e.g., changes in solar radiation and volcanic activity), contribute to these changes. Examples of data can include tables, graphs, and maps of global and regional temperatures and atmospheric gas levels.
6. (ii) Science and Engineering Practices. Analyzing and Interpreting Data. Analyze data using computational models in order to make valid and reliable scientific claims.
7. (iii) Disciplinary Core Ideas.
8. (I) Earth Materials and Systems. The geological record shows that changes to global and regional climate can be caused by interactions among changes in the Sun’s energy output or Earth’s orbit, tectonic events, ocean circulation, volcanic activity, glaciers, vegetation, and human activities. These changes can occur on a variety of time scales from sudden (e.g., volcanic ash clouds) to intermediate (ice ages) to very long-term (tectonic cycles).
9. (II) Weather and Climate. The foundation for Earth’s global climate system is the electromagnetic radiation from the Sun, as well as its reflection, absorption, storage, and redistribution among the atmosphere, ocean, and land systems, and this energy’s re-radiation into space.
10. (III) Earth and the Solar System. Cyclical changes in the shape of Earth’s orbit around the Sun, together with changes in the tilt of the planet’s axis of rotation, both occurring over hundreds of thousands of years, have altered the intensity and distribution of sunlight falling on the Earth. These phenomena cause a cycle of ice ages and other changes in climate.
11. (iv) Crosscutting Concepts. Cause and Effect. Empirical evidence is required to differentiate between cause and correlation and make claims about specific causes and effects.
12. (v) Connections to Scientific Literacy. Scientific Knowledge is Based on Empirical Evidence. Science arguments are strengthened by multiple lines of evidence supporting a single explanation.
13. (E) Performance expectation 5. Plan and conduct investigations of how the structure and resulting properties of water interact with the Earth’s materials and surface processes.
14. (i) Clarification Statement. Emphasis is on how the structure of water affects its physical and chemical properties. These properties can lead to mechanical and chemical investigations with water and a variety of solid materials to provide the evidence for connections between the hydrologic cycle and system interactions commonly known as the rock cycle. Examples of mechanical investigations include stream transportation and deposition using a stream table, erosion using variations in soil moisture content, or frost wedging by the expansion of water as it freezes. Examples of chemical investigations include chemical weathering and recrystallization (by testing the solubility of different materials) or melt generation (by examining how water lowers the melting temperature of most solids).
15. (ii) Science and Engineering Practices. Planning and Carrying Out Investigations. Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence.
16. (iii) Disciplinary Core Ideas. The Roles of Water in Earth’s Surface Processes. The abundance of liquid water on Earth’s surface and its unique combination of physical and chemical properties are central to the planet’s dynamics. These properties include water’s exceptional capacity to absorb, store, and release large amounts of energy; transmit sunlight; expand upon freezing; dissolve and transport materials; and lower the viscosities and melting points of rocks.
17. (iv) Crosscutting Concepts. Structure and Function. The functions and properties of natural and designed objects and systems can be inferred from their overall structure, the way their components are shaped and used, and the molecular substructures of their various materials.
18. (F) Performance expectation 6. Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.
19. (i) Clarification Statement. Emphasis is on modeling biogeochemical cycles that include the cycling of carbon through the ocean, atmosphere, soil, and biosphere (including humans), providing the foundation for living organisms. Examples of carbon cycling could include more carbon absorbed in the oceans leading to ocean acidification or more carbon present in the atmosphere; the stored carbon in fossil fuel deposits and carbon sinks, (e.g., crustal rocks, plant biomass, char).
20. (ii) Science and Engineering Practices. Developing and Using Models. Develop a model based on evidence to illustrate the relationships between systems or components of a system.
21. (iii) Disciplinary Core Ideas. Weather and Climate.
22. (I) Gradual atmospheric changes were due to plants and other organisms that captured carbon dioxide and released oxygen.
23. (II) Changes in the atmosphere due to human activity have increased carbon dioxide concentrations and thus affect climate.
24. (iv) Crosscutting Concepts. Energy and Matter. Energy drives the cycling of matter within and between systems.
25. (G) Performance expectation 7. Engage in argument from evidence for how the simultaneous co-evolution of Earth’s systems and life on Earth led to periods of stability and change over geologic time.
26. (i) Clarification Statement. Emphasis is on the dynamic causes, effects, and feedbacks between the biosphere and Earth’s other systems, whereby geoscience factors influence conditions for life, which in turn continuously alters Earth’s surface. Examples include how photosynthetic life altered the atmosphere through the production of oxygen, which in turn increased weathering rates and affected animal life; how microbial life on land increased the formation of soil, which in turn allowed for the development of land plant species; or how the changes in coral species created reefs that altered patterns of erosion and deposition along coastlines and provided habitats to support biodiversity. Geologic time scale should be considered with the emphasis above.
27. (ii) Assessment Boundary. Assessment does not include a comprehensive understanding of the mechanisms of how the biosphere interacts with all of Earth’s other systems.
28. (iii) Science and Engineering Practices. Engaging in Argument from Evidence. Construct an oral and written argument or counter-argument based on data and evidence.
29. (iv) Disciplinary Core Ideas.
30. (I) Weather and Climate. Gradual atmospheric changes were due to plants and other organisms that captured carbon dioxide and released oxygen.
31. (II) Biogeology. The many dynamic and delicate feedback mechanisms between the biosphere and other Earth systems cause a continual co-evolution of Earth’s surface and the life that exists on it.
32. (v) Crosscutting Concepts. Stability and Change. Much of science deals with constructing explanations of how things change and how they remain stable.
33. (3) Earth and Human Activities.
34. (A) Performance expectation 1. Construct an explanation based on evidence for how the availability of natural resources, occurrences of natural hazards, and changes in climate affect human activity.
35. (i) Clarification Statement. Examples of key natural resources could include access to fresh water (e.g., rivers, lakes, and groundwater), regions of fertile soils (e.g., river deltas), and high concentrations of minerals and fossil fuels. Examples of natural hazards could be from interior processes (e.g., volcanic eruptions, earthquakes), surface processes (e.g., tsunamis, landslides, mudslides, soil erosion), and severe weather (e.g., hurricanes, floods, droughts). Natural hazards and other geologic events exhibit some non-random patterns of occurrence. Examples of the results of changes in climate that can affect populations or drive mass migrations could include changes to sea level, regional patterns of temperature and precipitation, and the types of crops and livestock that can be raised.
36. (ii) Science and Engineering Practices. Constructing Explanations. Construct an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, theories, simulations, peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.
37. (iii) Disciplinary Core Ideas.
38. (I) Natural Resources. Resource availability has guided the development of human society.
39. (II) Natural Hazards. Natural hazards and other geologic events have shaped the course of human history; they have significantly altered the sizes of human populations and have driven human migrations.
40. (iv) Crosscutting Concepts. Cause and Effect. Empirical evidence is required to differentiate between cause and correlation and make claims about specific causes and effects.
41. (B) Performance expectation 2. Evaluate competing design solutions for developing, managing, and utilizing energy and mineral resources based on cost-benefit ratios on large and small scales.
42. (i) Clarification Statement. Emphasis is on the conservation, recycling, and reuse of resources (such as minerals and metals) where possible, and on minimizing impacts where it is not. Examples of large-scale solutions include developing best practices for agriculture; soil use; forestry; mining; and production of conventional, unconventional, or renewable energy resources. Examples of small-scale solutions could include mulching lawn clippings or adding biomass to gardens.
43. (ii) Science and Engineering Practices. Engaging in Argument from Evidence. Evaluate competing design solutions to a real-world problem based on scientific ideas and principles, empirical evidence, and logical arguments regarding relevant factors (e.g. economic, societal, environmental, ethical considerations).
44. (iii) Disciplinary Core Ideas.
45. (I) Natural Resources. All forms of energy production and other resource extraction have associated economic, social, environmental, and geopolitical costs and risks as well as benefits. New technologies and social regulations can change the balance of these factors.
46. (II) Developing Possible Solutions. When evaluating solutions, it is important to take into account a range of constraints, including cost, safety, reliability, and aesthetics, and to consider social, cultural, and environmental impacts.
47. (III) Influence of Science, Engineering, and Technology on Society and the Natural World.

a. Engineers continuously modify these technological systems by applying scientific knowledge and engineering design practices to increase benefits while decreasing costs and risks.

b. Analysis of costs and benefits is a critical aspect of decisions about technology.

1. (iv) Crosscutting Concepts. Scale, Proportion, and Quantity. Using concepts of orders of magnitude allows one to understand how a model at one scale relates to a model at another scale.
2. (v) Connections to Scientific Literacy. Science Addresses Questions About the Natural and Material World. Science knowledge indicates what can happen in natural systems - not what should happen. Many decisions are not made using science alone, but rely on social and cultural contexts to resolve issues.
3. (C) Performance expectation 3. Construct a scientific explanation from evidence for how geological processes cause uneven distribution of natural resources.
4. (i) Clarification Statement. Emphasis is on how geological processes have led to geological sedimentary basins that provide significant accumulations of crude oil and natural gas in some areas and not others, how geological processes lead to diverse soil profiles that support a diversity and range of agricultural crops, and how plate tectonics and other processes of ore formation lead to concentrations of mineral deposits. Examples of processes of ore formation include magmatic, sedimentary, weathering, and hydrothermal, all of which can connect to the geological history of a given location.
5. (ii) Science and Engineering Practices. Constructing Explanations. Construct an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, theories, simulations, peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.
6. (iii) Disciplinary Core Ideas. Global Climate Change. Most elements exist in Earth’s crust at concentrations too low to be extracted, but in some locations, where geological processes have concentrated them, extraction is economically viable.
7. (iv) Crosscutting Concepts. Cause and Effect. Empirical evidence is required to differentiate between cause and correlation and make claims about specific causes and effects.
8. (v) Connections to Scientific Literacy.
9. (I) Scientific Investigations Use a Variety of Methods. Science investigations use diverse methods and do not always use the same set of procedures to obtain data.
10. (II) Scientific Knowledge is Based on Empirical Evidence. Science arguments are strengthened by multiple lines of evidence supporting a single explanation.

Added at 42 Ok Reg, Number 21, effective 7-26-25