High School Science TEKS Standards

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to explain phenomena or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as Global Positioning System (GPS), Geographic Information System (GIS), weather balloons, buoys, water testing kits, meter sticks, metric rulers, pipettes, graduated cylinders, standard laboratory glassware, balances, timing devices, pH meters or probes, various data collecting probes, thermometers, calculators, computers, internet access, turbidity testing devices, hand magnifiers, work and disposable gloves, compasses, first aid kits, field guides, water quality test kits or probes, 30-meter tape measures, tarps, ripple tanks, trowels, screens, buckets, sediment samples equipment, cameras, flow meters, cast nets, kick nets, seines, computer models, spectrophotometers, stereomicroscopes, compound microscopes, clinometers, and field journals, various prepared slides, hand lenses, hot plates, Petri dishes, sampling nets, waders, leveling grade rods (Jason sticks), protractors, inclination and height distance calculators, samples of biological specimens or structures, core sampling equipment, fish tanks and associated supplies, and hydrometers;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using probeware, spreadsheets, lab notebooks or journals, models, diagrams, graphs paper, computers, or cellphone applications;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish between scientific hypotheses, theories, and laws.

The student knows the origin and potential uses of fresh water. The student is expected to:

identify sources of water in a watershed, including rainfall, groundwater, and surface water;

identify factors that contribute to how water flows through a watershed;

analyze water quantity and quality in a local watershed or aquifer; and

describe human uses of fresh water and how human freshwater use competes with that of other organisms.

The student knows that geological phenomena and fluid dynamics affect aquatic systems. The student is expected to:

examine basic principles of fluid dynamics, including hydrostatic pressure, density as a result of salinity, and buoyancy;

identify interrelationships between ocean currents, climates, and geologic features such as continental margins, active and passive margins, abyssal plains, island atolls, peninsulas, barrier islands, and hydrothermal vents;

explain how fluid dynamics causes upwelling and lake turnover; and

describe how erosion and deposition in river systems lead to formation of geologic features.

The student understands the types of aquatic ecosystems. The student is expected to:

differentiate among freshwater, brackish, and marine ecosystems; and

identify the major properties and components of different marine and freshwater life zones.

The student knows environmental adaptations of aquatic organisms. The student is expected to:

compare different traits in aquatic organisms using tools such as dichotomous keys;

describe how adaptations allow an organism to exist within an aquatic environment; and

compare adaptations of freshwater and marine organisms.

The student understands how human activities impact aquatic environments. The student is expected to:

analyze the cumulative impact of human population growth on an aquatic ecosystem;

predict effects of chemical, organic, physical, and thermal changes due to humans on the living and nonliving components of an aquatic ecosystem;

investigate the role of humans in unbalanced systems involving phenomena such as invasive species, fish farming, cultural eutrophication, or red tides;

analyze and discuss how human activities such as fishing, transportation, dams, and recreation influence aquatic environments;

describe the impact such as costs and benefits of various laws and policies such as The Endangered Species Act, right of capture laws, or Clean Water Act on aquatic systems; and

analyze the purpose and effectiveness of human efforts to restore aquatic ecosystems affected by human activities.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, planetariums, observatories, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student understands how the properties of water build the foundation of aquatic ecosystems. The student is expected to:

describe how the shape and polarity of the water molecule make it a "universal solvent" in aquatic systems;

identify how aquatic ecosystems are affected by water's properties of adhesion, cohesion, surface tension, heat capacity, and thermal conductivity; and

explain how the density of water is critical for organisms in cold environments.

Students know that aquatic environments are the product of interactions among Earth systems. The student is expected to:

identify key features and characteristics of atmospheric, geological, hydrological, and biological systems as they relate to aquatic environments;

describe the interrelatedness of atmospheric, geological, hydrological, and biological systems in aquatic ecosystems, including positive and negative feedback loops; and

evaluate environmental data using technology such as maps, visualizations, satellite data, Global Positioning System (GPS), Geographic Information System (GIS), weather balloons, and buoys to model the interactions that affect aquatic ecosystems.

The student knows about the interdependence and interactions that occur in aquatic environments. The student is expected to:

identify how energy flows and matter cycles through both freshwater and marine aquatic systems, including food webs, chains, and pyramids;

identify biological, chemical, geological, and physical components of an aquatic life zone as they relate to the organisms in it;

identify variables that affect the solubility of carbon dioxide and oxygen in water;

evaluate factors affecting aquatic population cycles such as lunar cycles, temperature variations, hours of daylight, and predator-prey relationships; and

identify the interdependence of organisms in an aquatic environment such as in a pond, a river, a lake, an ocean, or an aquifer and the biosphere.

The student conducts short-term and long-term studies on local aquatic environments. Local natural environments are to be preferred over artificial or virtual environments. The student is expected to:

evaluate data over a period of time from an established aquatic environment documenting seasonal changes and the behavior of organisms;

collect and analyze pH, salinity, temperature, mineral content, nitrogen compounds, dissolved oxygen, and turbidity data periodically, starting with baseline measurements; and

use data from short-term or long-term studies to analyze interrelationships between producers, consumers, and decomposers in aquatic ecosystems.

The student knows the role of cycles in an aquatic environment. The student is expected to:

identify the role of carbon, nitrogen, water, and nutrient cycles in an aquatic environment, including upwellings and turnovers;

examine the interrelationships between aquatic systems and climate and weather, including El Niño and La Niña, currents, and hurricanes; and

explain how tidal cycles influence intertidal ecology.

Science concepts. The student understands the benefits and challenges of expanding our knowledge of the universe. The student is expected to:

Science concepts. The student knows the scientific theories of cosmology. The student is expected to:

Science concepts. The student knows the structure of the universe and our relative place in it. The student is expected to:

Science concepts. The student understands the characteristics and life cycle of stars. The student is expected to:

Science concepts. The student knows that our Sun serves as a model for stellar activity. The student is expected to:

Science concepts. The student uses models to explain the formation, development, organization, and significance of solar system bodies. The student is expected to:

Science concepts. The student knows how astronomical tools collect and record information about celestial objects. The student is expected to:

Science concepts. The student models the cause of planetary seasons. The student is expected to:

Science concepts. The student observes and models the interactions within the Sun, Earth, and Moon system. The student is expected to:

Science concepts. The student knows our relative place in the solar system. The student is expected to:

Science concepts. The student conducts and explains astronomical observations made from the point of reference of Earth. The student is expected to:

Science concepts. The student understands how astronomy influenced and advanced civilizations. The student is expected to:

Scientific and engineering practices. The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

Scientific and engineering practices. The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

Scientific and engineering practices. The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

Scientific and engineering practices. The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to explain phenomena or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as gnomons; sundials; Planisphere; star charts; globe of the Earth; diffraction gratings; spectroscopes; color filters; lenses of multiple focal lengths; concave, plane, and convex mirrors; binoculars; telescopes; celestial sphere; online astronomical databases; and online access to observatories;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using graphs, charts, spreadsheets, and computer software;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish between scientific hypotheses, theories, and laws.

investigate the use of black body radiation curves and emission, absorption, and continuous spectra in the identification and classification of celestial objects;

calculate the relative light-gathering power of different-sized telescopes to compare telescopes for different applications;

analyze the importance and limitations of optical, infrared, and radio telescopes, gravitational wave detectors, and other ground-based technology; and

analyze the importance and limitations of space telescopes in the collection of astronomical data across the electromagnetic spectrum.

relate Newton's law of universal gravitation and Kepler's laws of planetary motion to the formation and motion of the planets and their satellites;

explore and communicate the origins and significance of planets, planetary rings, satellites, asteroids, comets, Oort cloud, and Kuiper belt objects;

compare the planets in terms of orbit, size, composition, rotation, atmosphere, natural satellites, magnetic fields, and geological activity; and

compare the factors essential to life on Earth such as temperature, water, gases, and gravitational and magnetic fields to conditions on other planets and their satellites.

identify the approximate mass, size, motion, temperature, structure, and composition of the Sun;

distinguish between nuclear fusion and nuclear fission and identify the source of energy within the Sun as nuclear fusion of hydrogen to helium;

describe the eleven-year solar cycle and the significance of sunspots; and

analyze the origins and effects of space weather, including the solar wind, coronal mass ejections, prominences, flares, and sunspots.

identify the characteristics of main sequence stars, including surface temperature, age, relative size, and composition;

describe and communicate star formation from nebulae to protostars to the development of main sequence stars;

evaluate the relationship between mass and fusion on stellar evolution;

compare how the mass of a main sequence star will determine its end state as a white dwarf, neutron star, or black hole;

describe the use of spectroscopy in obtaining physical data on celestial objects such as temperature, chemical composition, and relative motion;

use the Hertzsprung-Russell diagram to classify stars and plot and examine the life cycle of stars from birth to death;

illustrate how astronomers use geometric parallax to determine stellar distances and intrinsic luminosities; and

describe how stellar distances are determined by comparing apparent brightness and intrinsic luminosity when using spectroscopic parallax and the Leavitt relation for variable stars.

illustrate the structure and components of our Milky Way galaxy and model the size, location, and movement of our solar system within it;

compare spiral, elliptical, irregular, dwarf, and active galaxies;

develop and use models to explain how galactic evolution occurs through mergers and collisions;

describe the Local Group and its relation to larger-scale structures in the universe; and

evaluate the indirect evidence for the existence of dark matter.

describe and evaluate the historical development of evidence supporting the Big Bang Theory;

evaluate the limits of observational astronomy methods used to formulate the distance ladder;

evaluate the indirect evidence for the existence of dark energy;

describe the current scientific understanding of the evolution of the universe, including estimates for the age of the universe; and

describe current scientific hypotheses about the fate of the universe, including open and closed universes.

describe and communicate the historical development of human space flight and its challenges;

describe and communicate the uses and challenges of robotic space flight;

evaluate the evidence of the existence of habitable zones and potentially habitable planetary bodies in extrasolar planetary systems;

evaluate the impact on astronomy from light pollution, radio interference, and space debris;

examine and describe current developments and discoveries in astronomy; and

explore and explain careers that involve astronomy, space exploration, and the technologies developed through them.

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

develop explanations and propose solutions supported by data and models consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, planetariums, observatories, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

evaluate and communicate how ancient civilizations developed models of the universe using astronomical structures, instruments, and tools such as the astrolabe, gnomons, and charts and how those models influenced society, time keeping, and navigation;

research and evaluate the contributions of scientists, including Ptolemy, Copernicus, Tycho Brahe, Kepler, Galileo, and Newton, as astronomy progressed from a geocentric model to a heliocentric model; and

describe and explain the historical origins of the perceived patterns of constellations and the role of constellations in ancient and modern navigation.

observe, record, and analyze the apparent movement of the Sun, Moon, and stars and predict sunrise and sunset;

observe the movement of planets throughout the year and measure how their positions change relative to the constellations;

identify constellations such as Ursa Major, Ursa Minor, Orion, Cassiopeia, and constellations along the ecliptic and describe their importance; and

understand the difference between astronomy and astrology, the reasons for their historical conflation, and their eventual separation.

demonstrate the use of units of measurement in astronomy, including astronomical units and light years, minutes, and seconds;

model the scale, size, and distances of the Sun, Earth, and Moon system and identify the limitations of physical models; and

model the scale, sizes, and distances of the Sun and the planets in our solar system and identify the limitations of physical models.

model how the orbit and relative position of the Moon cause lunar phases and predict the timing of moonrise and moonset during each phase;

model how the orbit and relative position of the Moon cause lunar and solar eclipses; and

examine and investigate the dynamics of tides using the Sun, Earth, and Moon model.

examine the relationship of a planet's axial tilt to its potential seasons;

predict how changing latitudinal position affects the length of day and night throughout a planet's orbital year;

investigate the relationship between a planet's axial tilt, angle of incidence of sunlight, and concentration of solar energy; and

explain the significance of Earth's solstices and equinoxes.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to explain phenomena or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as gnomons; sundials; Planisphere; star charts; globe of the Earth; diffraction gratings; spectroscopes; color filters; lenses of multiple focal lengths; concave, plane, and convex mirrors; binoculars; telescopes; celestial sphere; online astronomical databases; and online access to observatories;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using graphs, charts, spreadsheets, and computer software;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish between scientific hypotheses, theories, and laws.

The student knows how astronomical tools collect and record information about celestial objects. The student is expected to:

investigate the use of black body radiation curves and emission, absorption, and continuous spectra in the identification and classification of celestial objects;

calculate the relative light-gathering power of different-sized telescopes to compare telescopes for different applications;

analyze the importance and limitations of optical, infrared, and radio telescopes, gravitational wave detectors, and other ground-based technology; and

analyze the importance and limitations of space telescopes in the collection of astronomical data across the electromagnetic spectrum.

The student uses models to explain the formation, development, organization, and significance of solar system bodies. The student is expected to:

relate Newton's law of universal gravitation and Kepler's laws of planetary motion to the formation and motion of the planets and their satellites;

explore and communicate the origins and significance of planets, planetary rings, satellites, asteroids, comets, Oort cloud, and Kuiper belt objects;

compare the planets in terms of orbit, size, composition, rotation, atmosphere, natural satellites, magnetic fields, and geological activity; and

compare the factors essential to life on Earth such as temperature, water, gases, and gravitational and magnetic fields to conditions on other planets and their satellites.

The student knows that our Sun serves as a model for stellar activity. The student is expected to:

identify the approximate mass, size, motion, temperature, structure, and composition of the Sun;

distinguish between nuclear fusion and nuclear fission and identify the source of energy within the Sun as nuclear fusion of hydrogen to helium;

describe the eleven-year solar cycle and the significance of sunspots; and

analyze the origins and effects of space weather, including the solar wind, coronal mass ejections, prominences, flares, and sunspots.

The student understands the characteristics and life cycle of stars. The student is expected to:

identify the characteristics of main sequence stars, including surface temperature, age, relative size, and composition;

describe and communicate star formation from nebulae to protostars to the development of main sequence stars;

evaluate the relationship between mass and fusion on stellar evolution;

compare how the mass of a main sequence star will determine its end state as a white dwarf, neutron star, or black hole;

describe the use of spectroscopy in obtaining physical data on celestial objects such as temperature, chemical composition, and relative motion;

use the Hertzsprung-Russell diagram to classify stars and plot and examine the life cycle of stars from birth to death;

illustrate how astronomers use geometric parallax to determine stellar distances and intrinsic luminosities; and

describe how stellar distances are determined by comparing apparent brightness and intrinsic luminosity when using spectroscopic parallax and the Leavitt relation for variable stars.

The student knows the structure of the universe and our relative place in it. The student is expected to:

illustrate the structure and components of our Milky Way galaxy and model the size, location, and movement of our solar system within it;

compare spiral, elliptical, irregular, dwarf, and active galaxies;

develop and use models to explain how galactic evolution occurs through mergers and collisions;

describe the Local Group and its relation to larger-scale structures in the universe; and

evaluate the indirect evidence for the existence of dark matter.

The student knows the scientific theories of cosmology. The student is expected to:

describe and evaluate the historical development of evidence supporting the Big Bang Theory;

evaluate the limits of observational astronomy methods used to formulate the distance ladder;

evaluate the indirect evidence for the existence of dark energy;

describe the current scientific understanding of the evolution of the universe, including estimates for the age of the universe; and

describe current scientific hypotheses about the fate of the universe, including open and closed universes.

The student understands the benefits and challenges of expanding our knowledge of the universe. The student is expected to:

describe and communicate the historical development of human space flight and its challenges;

describe and communicate the uses and challenges of robotic space flight;

evaluate the evidence of the existence of habitable zones and potentially habitable planetary bodies in extrasolar planetary systems;

evaluate the impact on astronomy from light pollution, radio interference, and space debris;

examine and describe current developments and discoveries in astronomy; and

explore and explain careers that involve astronomy, space exploration, and the technologies developed through them.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, planetariums, observatories, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student understands how astronomy influenced and advanced civilizations. The student is expected to:

evaluate and communicate how ancient civilizations developed models of the universe using astronomical structures, instruments, and tools such as the astrolabe, gnomons, and charts and how those models influenced society, time keeping, and navigation;

research and evaluate the contributions of scientists, including Ptolemy, Copernicus, Tycho Brahe, Kepler, Galileo, and Newton, as astronomy progressed from a geocentric model to a heliocentric model; and

describe and explain the historical origins of the perceived patterns of constellations and the role of constellations in ancient and modern navigation.

The student conducts and explains astronomical observations made from the point of reference of Earth. The student is expected to:

observe, record, and analyze the apparent movement of the Sun, Moon, and stars and predict sunrise and sunset;

observe the movement of planets throughout the year and measure how their positions change relative to the constellations;

identify constellations such as Ursa Major, Ursa Minor, Orion, Cassiopeia, and constellations along the ecliptic and describe their importance; and

understand the difference between astronomy and astrology, the reasons for their historical conflation, and their eventual separation.

The student knows our relative place in the solar system. The student is expected to:

demonstrate the use of units of measurement in astronomy, including astronomical units and light years, minutes, and seconds;

model the scale, size, and distances of the Sun, Earth, and Moon system and identify the limitations of physical models; and

model the scale, sizes, and distances of the Sun and the planets in our solar system and identify the limitations of physical models.

The student observes and models the interactions within the Sun, Earth, and Moon system. The student is expected to:

model how the orbit and relative position of the Moon cause lunar phases and predict the timing of moonrise and moonset during each phase;

model how the orbit and relative position of the Moon cause lunar and solar eclipses; and

examine and investigate the dynamics of tides using the Sun, Earth, and Moon model.

The student models the cause of planetary seasons. The student is expected to:

examine the relationship of a planet's axial tilt to its potential seasons;

predict how changing latitudinal position affects the length of day and night throughout a planet's orbital year;

investigate the relationship between a planet's axial tilt, angle of incidence of sunlight, and concentration of solar energy; and

explain the significance of Earth's solstices and equinoxes.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to answer questions, explain phenomena, or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as microscopes, slides, Petri dishes, laboratory glassware, metric rulers, digital balances, pipets, filter paper, micropipettes, gel electrophoresis and polymerase chain reaction (PCR) apparatuses, microcentrifuges, water baths, incubators, thermometers, hot plates, data collection probes, test tube holders, lab notebooks or journals, hand lenses, and models, diagrams, or samples of biological specimens or structures;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using scatter plots, line graphs, bar graphs, charts, data tables, digital tools, diagrams, scientific drawings, and student-prepared models;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish among scientific hypotheses, theories, and laws.

The student knows evolutionary theory is a scientific explanation for the unity and diversity of life that has multiple mechanisms. The student is expected to:

analyze and evaluate how natural selection produces change in populations and not in individuals;

analyze and evaluate how the elements of natural selection, including inherited variation, the potential of a population to produce more offspring than can survive, and a finite supply of environmental resources, result in differential reproductive success;

analyze and evaluate how natural selection may lead to speciation; and

analyze evolutionary mechanisms other than natural selection, including genetic drift, gene flow, mutation, and genetic recombination, and their effect on the gene pool of a population.

The student knows the significance of matter cycling, energy flow, and enzymes in living organisms. The student is expected to:

explain how matter is conserved and energy is transferred during photosynthesis and cellular respiration using models, including the chemical equations for these processes; and

investigate and explain the role of enzymes in facilitating cellular processes.

The student knows that multicellular organisms are composed of multiple systems that interact to perform complex functions. The student is expected to:

analyze the interactions that occur among systems that perform the functions of regulation, nutrient absorption, reproduction, and defense from injury or illness in animals; and

explain how the interactions that occur among systems that perform functions of transport, reproduction, and response in plants are facilitated by their structures.

The student knows that interactions at various levels of organization occur within an ecosystem to maintain stability. The student is expected to:

investigate and evaluate how ecological relationships, including predation, parasitism, commensalism, mutualism, and competition, influence ecosystem stability;

analyze how ecosystem stability is affected by disruptions to the cycling of matter and flow of energy through trophic levels using models;

explain the significance of the carbon and nitrogen cycles to ecosystem stability and analyze the consequences of disrupting these cycles; and

explain how environmental change, including change due to human activity, affects biodiversity and analyze how changes in biodiversity impact ecosystem stability.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models and consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student knows that biological structures at multiple levels of organization perform specific functions and processes that affect life. The student is expected to:

relate the functions of different types of biomolecules, including carbohydrates, lipids, proteins, and nucleic acids, to the structure and function of a cell;

compare and contrast prokaryotic and eukaryotic cells, including their complexity, and compare and contrast scientific explanations for cellular complexity;

investigate homeostasis through the cellular transport of molecules; and

compare the structures of viruses to cells and explain how viruses spread and cause disease.

The student knows how an organism grows and the importance of cell differentiation. The student is expected to:

explain the importance of the cell cycle to the growth of organisms, including an overview of the stages of the cell cycle and deoxyribonucleic acid (DNA) replication models;

explain the process of cell specialization through cell differentiation, including the role of environmental factors; and

relate disruptions of the cell cycle to how they lead to the development of diseases such as cancer.

The student knows the role of nucleic acids in gene expression. The student is expected to:

identify components of DNA, explain how the nucleotide sequence specifies some traits of an organism, and examine scientific explanations for the origin of DNA;

describe the significance of gene expression and explain the process of protein synthesis using models of DNA and ribonucleic acid (RNA);

identify and illustrate changes in DNA and evaluate the significance of these changes; and

discuss the importance of molecular technologies such as polymerase chain reaction (PCR), gel electrophoresis, and genetic engineering that are applicable in current research and engineering practices.

The student knows the role of nucleic acids and the principles of inheritance and variation of traits in Mendelian and non-Mendelian genetics. The student is expected to:

analyze the significance of chromosome reduction, independent assortment, and crossing-over during meiosis in increasing diversity in populations of organisms that reproduce sexually; and

predict possible outcomes of various genetic combinations using monohybrid and dihybrid crosses, including non-Mendelian traits of incomplete dominance, codominance, sex-linked traits, and multiple alleles.

The student knows evolutionary theory is a scientific explanation for the unity and diversity of life that has multiple lines of evidence. The student is expected to:

analyze and evaluate how evidence of common ancestry among groups is provided by the fossil record, biogeography, and homologies, including anatomical, molecular, and developmental; and

examine scientific explanations for varying rates of change such as gradualism, abrupt appearance, and stasis in the fossil record.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to answer questions, explain phenomena, or design solutions using appropriate tools and models. The student is expected to:

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as Safety Data Sheets (SDS), scientific or graphing calculators, computers and probes, electronic balances, an adequate supply of consumable chemicals, and sufficient scientific glassware such as beakers, Erlenmeyer flasks, pipettes, graduated cylinders, volumetric flasks, and burettes;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using oral or written lab reports, labeled drawings, particle diagrams, charts, tables, graphs, journals, summaries, or technology-based reports;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish between scientific hypotheses, theories, and laws.

The student understands the principles of the kinetic molecular theory and ideal gas behavior. The student is expected to:

describe the postulates of the kinetic molecular theory;

describe and calculate the relationships among volume, pressure, number of moles, and temperature for an ideal gas; and

define and apply Dalton's law of partial pressure.

The student understands and can apply the factors that influence the behavior of solutions. The student is expected to:

describe the unique role of water in solutions in terms of polarity;

distinguish among types of solutions, including electrolytes and nonelectrolytes and unsaturated, saturated, and supersaturated solutions;

investigate how solid and gas solubilities are influenced by temperature using solubility curves and how rates of dissolution are influenced by temperature, agitation, and surface area;

investigate the general rules regarding solubility and predict the solubility of the products of a double replacement reaction;

calculate the concentration of solutions in units of molarity; and

calculate the dilutions of solutions using molarity.

The student understands and applies various rules regarding acids and bases. The student is expected to:

name and write the chemical formulas for acids and bases using IUPAC nomenclature rules;

define acids and bases and distinguish between Arrhenius and Bronsted-Lowry definitions;

differentiate between strong and weak acids and bases;

predict products in acid-base reactions that form water; and

define pH and calculate the pH of a solution using the hydrogen ion concentration.

The student understands the energy changes that occur in chemical reactions. The student is expected to:

explain everyday examples that illustrate the four laws of thermodynamics;

investigate the process of heat transfer using calorimetry;

classify processes as exothermic or endothermic and represent energy changes that occur in chemical reactions using thermochemical equations or graphical analysis; and

perform calculations involving heat, mass, temperature change, and specific heat.

The student understands the basic processes of nuclear chemistry. The student is expected to:

describe the characteristics of alpha, beta, and gamma radioactive decay processes in terms of balanced nuclear equations;

compare fission and fusion reactions; and

give examples of applications of nuclear phenomena such as nuclear stability, radiation therapy, diagnostic imaging, solar cells, and nuclear power.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models and consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student understands the development of the Periodic Table and applies its predictive power. The student is expected to:

explain the development of the Periodic Table over time using evidence such as chemical and physical properties;

predict the properties of elements in chemical families, including alkali metals, alkaline earth metals, halogens, noble gases, and transition metals, based on valence electrons patterns using the Periodic Table; and

analyze and interpret elemental data, including atomic radius, atomic mass, electronegativity, ionization energy, and reactivity to identify periodic trends.

The student understands the development of atomic theory and applies it to real-world phenomena. The student is expected to:

construct models using Dalton's Postulates, Thomson's discovery of electron properties, Rutherford's nuclear atom, Bohr's nuclear atom, and Heisenberg's Uncertainty Principle to show the development of modern atomic theory over time;

describe the structure of atoms and ions, including the masses, electrical charges, and locations of protons and neutrons in the nucleus and electrons in the electron cloud;

investigate the mathematical relationship between energy, frequency, and wavelength of light using the electromagnetic spectrum and relate it to the quantization of energy in the emission spectrum;

calculate average atomic mass of an element using isotopic composition; and

construct models to express the arrangement of electrons in atoms of representative elements using electron configurations and Lewis dot structures.

The student knows how atoms form ionic, covalent, and metallic bonds. The student is expected to:

construct an argument to support how periodic trends such as electronegativity can predict bonding between elements;

name and write the chemical formulas for ionic and covalent compounds using International Union of Pure and Applied Chemistry (IUPAC) nomenclature rules;

classify and draw electron dot structures for molecules with linear, bent, trigonal planar, trigonal pyramidal, and tetrahedral molecular geometries as explained by Valence Shell Electron Pair Repulsion (VSEPR) theory; and

analyze the properties of ionic, covalent, and metallic substances in terms of intramolecular and intermolecular forces.

The student understands how matter is accounted for in chemical substances. The student is expected to:

define mole and apply the concept of molar mass to convert between moles and grams;

calculate the number of atoms or molecules in a sample of material using Avogadro's number;

calculate percent composition of compounds; and

differentiate between empirical and molecular formulas.

The student understands how matter is accounted for in chemical reactions. The student is expected to:

interpret, write, and balance chemical equations, including synthesis, decomposition, single replacement, double replacement, and combustion reactions using the law of conservation of mass;

differentiate among acid-base reactions, precipitation reactions, and oxidation-reduction reactions;

perform stoichiometric calculations, including determination of mass relationships, gas volume relationships, and percent yield; and

describe the concept of limiting reactants in a balanced chemical equation.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to explain phenomena or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as a drawing compass, magnetic compass, bar magnets, topographical and geological maps, satellite imagery and other remote sensing data, Geographic Information Systems (GIS), Global Positioning System (GPS), hand lenses, and fossil and rock sample kits;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using scatter plots, line graphs, bar graphs, charts, data tables, digital tools, diagrams, scientific drawings, and student-prepared models;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish between scientific hypotheses, theories, and laws.

The student knows how the physical and chemical properties of the ocean affect its structure and flow of energy. The student is expected to:

describe how the composition and structure of the oceans leads to thermohaline circulation and its periodicity;

model and explain how changes to the composition, structure, and circulation of deep oceans affect thermohaline circulation using data on energy flow, ocean basin structure, and changes in polar ice caps and glaciers; and

analyze how global surface ocean circulation is the result of wind, tides, the Coriolis effect, water density differences, and the shape of the ocean basins.

The student knows that dynamic and complex interactions among Earth's systems produce climate and weather. The student is expected to:

analyze how energy transfer through Milankovitch cycles, albedo, and differences in atmospheric and surface absorption are mechanisms of climate;

describe how Earth's atmosphere is chemically and thermally stratified and how solar radiation interacts with the layers to cause the ozone layer, the jet stream, Hadley and Ferrel cells, and other atmospheric phenomena;

model how greenhouse gases trap thermal energy near Earth's surface;

evaluate how the combination of multiple feedback loops alter global climate;

investigate and analyze evidence for climate changes over Earth's history using paleoclimate data, historical records, and measured greenhouse gas levels;

explain how the transfer of thermal energy among the hydrosphere, lithosphere, and atmosphere influences weather; and

describe how changing surface-ocean conditions, including El Niño-Southern Oscillation, affect global weather and climate patterns.

The student understands how Earth's systems affect and are affected by human activities, including resource use and management. The student is expected to:

evaluate the impact on humans of natural changes in Earth's systems such as earthquakes, tsunamis, and volcanic eruptions;

analyze the impact on humans of naturally occurring extreme weather events such as flooding, hurricanes, tornadoes, and thunderstorms;

analyze the natural and anthropogenic factors that affect the severity and frequency of extreme weather events and the hazards associated with these events;

analyze recent global ocean temperature data to predict the consequences of changing ocean temperature on evaporation, sea level, algal growth, coral bleaching, and biodiversity;

predict how human use of Texas's naturally occurring resources such as fossil fuels, minerals, soil, solar energy, and wind energy directly and indirectly changes the cycling of matter and energy through Earth's systems; and

explain the cycling of carbon through different forms among Earth's systems and how biological processes have caused major changes to the carbon cycle in those systems over Earth's history.

The student explores global policies and careers related to the life cycles of Earth's resources. The student is expected to:

analyze the policies related to resources from discovery to disposal, including economics, health, technological advances, resource type, concentration and location, waste disposal and recycling, mitigation efforts, and environmental impacts; and

explore global and Texas-based careers that involve the exploration, extraction, production, use, disposal, regulation, and protection of Earth's resources.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, planetariums, observatories, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student understands the formation of the Earth and how objects in the solar system affect Earth's systems. The student is expected to:

analyze how gravitational condensation of solar nebular gas and dust can lead to the accretion of planetesimals and protoplanets;

identify comets, asteroids, meteoroids, and planets in the solar system and describe how they affect the Earth and Earth's systems; and

explore the historical and current hypotheses for the origin of the Moon, including the collision of Earth with a Mars-sized planetesimal.

The student knows the evidence for the formation and composition of Earth's atmosphere, hydrosphere, biosphere, and geosphere. The student is expected to:

describe how impact accretion, gravitational compression, radioactive decay, and cooling differentiated proto-Earth into layers;

evaluate the roles of volcanic outgassing and water-bearing comets in developing Earth's atmosphere and hydrosphere;

evaluate the evidence for changes to the chemical composition of Earth's atmosphere prior to the introduction of oxygen;

evaluate scientific hypotheses for the origin of life through abiotic chemical processes; and

describe how the production of oxygen by photosynthesis affected the development of the atmosphere, hydrosphere, geosphere, and biosphere.

The student knows that rocks and fossils provide evidence for geologic chronology, biological evolution, and environmental changes. The student is expected to:

describe the development of multiple radiometric dating methods and analyze their precision, reliability, and limitations in calculating the ages of igneous rocks from Earth, the Moon, and meteorites;

apply relative dating methods, principles of stratigraphy, and index fossils to determine the chronological order of rock layers;

construct a model of the geological time scale using relative and absolute dating methods to represent Earth's approximate 4.6-billion-year history;

explain how sedimentation, fossilization, and speciation affect the degree of completeness of the fossil record;

describe how evidence of biozones and faunal succession in rock layers reveal information about the environment at the time those rocks were deposited and the dynamic nature of the Earth; and

analyze data from rock and fossil succession to evaluate the evidence for and significance of mass extinctions, major climatic changes, and tectonic events.

The student knows how the Earth's interior dynamics and energy flow drive geological processes on Earth's surface. The student is expected to:

evaluate heat transfer through Earth's systems by convection and conduction and include its role in plate tectonics and volcanism;

develop a model of the physical, mechanical, and chemical composition of Earth's layers using evidence from Earth's magnetic field, the composition of meteorites, and seismic waves;

investigate how new conceptual interpretations of data and innovative geophysical technologies led to the current theory of plate tectonics;

describe how heat and rock composition affect density within Earth's interior and how density influences the development and motion of Earth's tectonic plates;

explain how plate tectonics accounts for geologic processes, including sea floor spreading and subduction, and features, including ocean ridges, rift valleys, earthquakes, volcanoes, mountain ranges, hot spots, and hydrothermal vents;

calculate the motion history of tectonic plates using equations relating rate, time, and distance to predict future motions, locations, and resulting geologic features;

distinguish the location, type, and relative motion of convergent, divergent, and transform plate boundaries using evidence from the distribution of earthquakes and volcanoes; and

evaluate the role of plate tectonics with respect to long-term global changes in Earth's subsystems such as continental buildup, glaciation, sea level fluctuations, mass extinctions, and climate change.

The student knows that the lithosphere continuously changes as a result of dynamic and complex interactions among Earth's systems. The student is expected to:

interpret Earth surface features using a variety of methods such as satellite imagery, aerial photography, and topographic and geologic maps using appropriate technologies;

investigate and model how surface water and ground water change the lithosphere through chemical and physical weathering and how they serve as valuable natural resources;

model the processes of mass wasting, erosion, and deposition by water, wind, ice, glaciation, gravity, and volcanism in constantly reshaping Earth's surface; and

evaluate how weather and human activity affect the location, quality, and supply of available freshwater resources.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to explain phenomena or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as meter sticks, metric rulers, pipettes, graduated cylinders, standard laboratory glassware, balances, timing devices, pH meters or probes, various data collecting probes, thermometers, calculators, computers, internet access, turbidity testing devices, hand magnifiers, work and disposable gloves, compasses, first aid kits, binoculars, field guides, water quality test kits or probes, soil test kits or probes, 30 meter tape measures, tarps, shovels, trowels, screens, buckets, rock and mineral samples equipment, air quality testing devices, cameras, flow meters, Global Positioning System (GPS) units, Geographic Information System (GIS) software, computer models, densiometers, spectrophotometers, stereomicroscopes, compound microscopes, clinometers, field journals, various prepared slides, hand lenses, hot plates, Petri dishes, sampling nets, waders, leveling grade rods (Jason sticks), protractors, inclination and height distance calculators, samples of biological specimens or structures, core sampling equipment, and kick nets;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using probeware, spreadsheets, lab notebooks or journals, models, diagrams, graphs paper, computers, or cellphone applications;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish between scientific hypotheses, theories, and laws.

The student knows how humans impact environmental systems through emissions and pollutants. The student is expected to:

identify sources of emissions in air, soil, and water, including point and nonpoint sources;

distinguish how an emission becomes a pollutant based on its concentration, toxicity, reactivity, and location within the environment;

investigate the effects of pollutants such as chlorofluorocarbons, greenhouse gases, pesticide runoff, nuclear waste, aerosols, metallic ions, and heavy metals, as well as thermal, light, and noise pollution;

evaluate indicators of air, soil, and water quality against regulatory standards to determine the health of an ecosystem; and

distinguish between the causes and effects of global warming and ozone depletion, including the causes, the chemicals involved, the atmospheric layer, the environmental effects, the human health effects, and the relevant wavelengths on the electromagnetic spectrum (IR and UV).

The student understands how individual and collective actions impact environmental systems. The student is expected to:

evaluate the negative effects of human activities on the environment, including overhunting, overfishing, ecotourism, all-terrain vehicles, and personal watercraft;

evaluate the positive effects of human activities on the environment, including habitat restoration projects, species preservation efforts, nature conservancy groups, game and wildlife management, and ecotourism; and

research the advantages and disadvantages of "going green" such as organic gardening and farming, natural methods of pest control, hydroponics, xeriscaping, energy-efficient homes and appliances, and hybrid cars.

The student understands how ethics and economic priorities influence environmental decisions. The student is expected to:

evaluate cost-benefit trade-offs of commercial activities such as municipal development, food production, deforestation, over-harvesting, mining, and use of renewable and non-renewable energy sources;

evaluate the economic impacts of individual actions on the environment such as overbuilding, habitat destruction, poaching, and improper waste disposal;

analyze how ethical beliefs influence environmental scientific and engineering practices such as methods for food production, water distribution, energy production, and the extraction of minerals;

discuss the impact of research and technology on social ethics and legal practices in situations such as the design of new buildings, recycling, or emission standards; and

argue from evidence whether or not a healthy economy and a healthy environment are mutually exclusive.

The student knows how legislation mediates human impacts on the environment. The student is expected to:

describe past and present state and national legislation, including Texas automobile emissions regulations, the National Park Service Act, the Clean Air Act, the Clean Water Act, the Soil and Water Resources Conservation Act, and the Endangered Species Act; and

evaluate the goals and effectiveness of past and present international agreements such as the environmental Antarctic Treaty System, the Montreal Protocol, the Kyoto Protocol, and the Paris Climate Accord.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, planetariums, observatories, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student knows the relationships of biotic and abiotic factors within habitats, ecosystems, and biomes. The student is expected to:

identify native plants and animals within a local ecosystem and compare their roles to those of plants and animals in other biomes, including aquatic, grassland, forest, desert, and tundra;

explain the cycling of water, phosphorus, carbon, silicon, and nitrogen through ecosystems, including sinks, and the human interactions that alter these cycles using tools such as models;

evaluate the effects of fluctuations in abiotic factors on local ecosystems and local biomes;

measure the concentration of dissolved substances such as dissolved oxygen, chlorides, and nitrates and describe their impacts on an ecosystem;

use models to predict how the introduction of an invasive species may alter the food chain and affect existing populations in an ecosystem;

use models to predict how species extinction may alter the food chain and affect existing populations in an ecosystem; and

predict changes that may occur in an ecosystem if genetic diversity is increased or decreased.

The student knows the interrelationships among the resources within the local environmental system. The student is expected to:

compare and contrast land use and management methods and how they affect land attributes such as fertility, productivity, economic value, and ecological stability;

relate how water sources, management, and conservation affect water uses and quality;

document the use and conservation of both renewable and non-renewable resources as they pertain to sustainability;

identify how changes in limiting resources such as water, food, and energy affect local ecosystems;

analyze and evaluate the economic significance and interdependence of resources within the local environmental system; and

evaluate the impact of waste management methods such as reduction, reuse, recycling, upcycling, and composting on resource availability in the local environment.

The student knows the sources and flow of energy through an environmental system. The student is expected to:

describe the interactions between the components of the geosphere, hydrosphere, cryosphere, atmosphere, and biosphere;

relate biogeochemical cycles to the flow of energy in ecosystems, including energy sinks such as oil, natural gas, and coal deposits;

explain the flow of heat energy in an ecosystem, including conduction, convection, and radiation; and

identify and describe how energy is used, transformed, and conserved as it flows through ecosystems.

The student knows the relationship between carrying capacity and changes in populations and ecosystems. The student is expected to:

compare exponential and logistical population growth using graphical representations;

identify factors that may alter carrying capacity such as disease; natural disaster; available food, water, and livable space; habitat fragmentation; and periodic changes in weather;

calculate changes in population size in ecosystems; and

analyze and make predictions about the impact on populations of geographic locales due to diseases, birth and death rates, urbanization, and natural events such as migration and seasonal changes.

The student knows that environments change naturally. The student is expected to:

analyze and describe how natural events such as tectonic movement, volcanic events, fires, tornadoes, hurricanes, flooding, and tsunamis affect natural populations;

explain how regional changes in the environment may have global effects;

examine how natural processes such as succession and feedback loops can restore habitats and ecosystems;

describe how temperature inversions have short-term and long-term effects, including El Niño and La Niña oscillations, ice cap and glacial melting, and changes in ocean surface temperatures; and

analyze the impact of natural global climate change on ice caps, glaciers, ocean currents, and surface temperatures.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to answer questions, explain phenomena, or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as data-collecting probes, software applications, the internet, standard laboratory glassware, metric rulers, meter sticks, spring scales, multimeters, Gauss meters, wires, batteries, light bulbs, switches, magnets, electronic balances, mass sets, Celsius thermometers, hot plates, an adequate supply of consumable chemicals, lab notebooks or journals, timing devices, models, and diagrams;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using labeled drawings and diagrams, graphic organizers, charts, tables, and graphs;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish between scientific hypotheses, theories, and laws.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models and consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student knows the relationship between force and motion in everyday life. The student is expected to:

investigate, analyze, and model motion in terms of position, velocity, acceleration, and time using tables, graphs, and mathematical relationships;

analyze data to explain the relationship between mass and acceleration in terms of the net force on an object in one dimension using force diagrams, tables, and graphs;

apply the concepts of momentum and impulse to design, evaluate, and refine a device to minimize the net force on objects during collisions such as those that occur during vehicular accidents, sports activities, or the dropping of personal electronic devices;

describe the nature of the four fundamental forces: gravitation; electromagnetic; the strong and weak nuclear forces, including fission and fusion; and mass-energy equivalency; and

construct and communicate an explanation based on evidence for how changes in mass, charge, and distance affect the strength of gravitational and electrical forces between two objects.

The student knows the impact of energy transfer and energy conservation in everyday life. The student is expected to:

design and construct series and parallel circuits that model real-world circuits such as in-home wiring, automobile wiring, and simple electrical devices to evaluate the transfer of electrical energy;

design, evaluate, and refine a device that generates electrical energy through the interaction of electric charges and magnetic fields;

plan and conduct an investigation to provide evidence that energy is conserved within a closed system;

investigate and demonstrate the movement of thermal energy through solids, liquids, and gases by convection, conduction, and radiation such as weather, living, and mechanical systems;

plan and conduct an investigation to evaluate the transfer of energy or information through different materials by different types of waves such as wireless signals, ultraviolet radiation, and microwaves;

construct and communicate an evidence-based explanation for how wave interference, reflection, and refraction are used in technology such as medicine, communication, and scientific research; and

evaluate evidence from multiple sources to critique the advantages and disadvantages of various renewable and nonrenewable energy sources and their impact on society and the environment.

The student knows that relationships exist between the structure and properties of matter. The student is expected to:

model basic atomic structure and relate an element's atomic structure to its bonding, reactivity, and placement on the Periodic Table;

use patterns within the Periodic Table to predict the relative physical and chemical properties of elements;

explain how physical and chemical properties of substances are related to their usage in everyday life such as in sunscreen, cookware, industrial applications, and fuels;

explain how electrons can transition from a high energy level to a low energy state, emitting photons at different frequencies for different energy transitions;

explain how atomic energy levels and emission spectra present evidence for the wave particle duality; and

plan and conduct an investigation to provide evidence that the rate of reaction or dissolving is affected by multiple factors such as particle size, stirring, temperature, and concentration.

The student knows that changes in matter affect everyday life. The student is expected to:

investigate how changes in properties are indicative of chemical reactions such as hydrochloric acid with a metal, oxidation of metal, combustion, and neutralizing an acid with a base;

develop and use models to balance chemical equations and support the claim that atoms, and therefore mass, are conserved during a chemical reaction;

research and communicate the uses, advantages, and disadvantages of nuclear reactions in current technologies; and

construct and communicate an evidence-based explanation of the environmental impact of the end-products of chemical reactions such as those that may result in degradation of water, soil, air quality, and global climate change.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to answer questions, explain phenomena, or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems based on observations or information from text, phenomena, models, or investigations;

apply scientific practices to plan and conduct descriptive, comparative, and experimental investigations, and use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use appropriate tools such as balances, ballistic carts or equivalent, batteries, computers, constant velocity cars, convex lenses, copper wire, discharge tubes with power supply (H, He, Ne, Ar), data acquisition probes and software, dynamics and force demonstration equipment, electrostatic generators, electrostatic kits, friction blocks, graph paper, graphing technology, hand-held visual spectroscopes, inclined planes, iron filings, lab masses, laser pointers, magnets, magnetic compasses, metric rulers, motion detectors, multimeters (current, voltage, resistance), optics bench, optics kit, photogates, plane mirrors, prisms, protractors, pulleys, resistors, rope or string, scientific calculators, stopwatches, springs, spring scales, switches, tuning forks, wave generators, or other equipment and materials that will produce the same results;

collect quantitative data using the International System of Units (SI) and qualitative data as evidence;

organize quantitative and qualitative data using bar charts, line graphs, scatter plots, data tables, labeled diagrams, and conceptual mathematical relationships;

develop and use models to represent phenomena, systems, processes, or solutions to engineering problems; and

distinguish among scientific hypotheses, theories, and laws.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials;

analyze data by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data; and

evaluate experimental and engineering designs.

The student develops evidence-based explanations and communicates findings, conclusions, and proposed solutions. The student is expected to:

develop explanations and propose solutions supported by data and models and consistent with scientific ideas, principles, and theories;

communicate explanations and solutions individually and collaboratively in a variety of settings and formats; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as related to the content; and

research and explore resources such as museums, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers.

The student knows and applies the laws governing motion in a variety of situations. The student is expected to:

analyze different types of motion by generating and interpreting position versus time, velocity versus time, and acceleration versus time using hand graphing and real-time technology such as motion detectors, photogates, or digital applications;

define scalar and vector quantities related to one- and two-dimensional motion and combine vectors using both graphical vector addition and the Pythagorean theorem;

describe and analyze motion in one dimension using equations with the concepts of distance, displacement, speed, velocity, frames of reference, and acceleration;

describe and analyze acceleration in uniform circular and horizontal projectile motion in two dimensions using equations; (E) explain and apply the concepts of equilibrium and inertia as represented by Newton's first law of motion using relevant real-world examples such as rockets, satellites, and automobile safety devices;

calculate the effect of forces on objects, including tension, friction, normal, gravity, centripetal, and applied forces, using free body diagrams and the relationship between force and acceleration as represented by Newton's second law of motion;

illustrate and analyze the simultaneous forces between two objects as represented in Newton's third law of motion using free body diagrams and in an experimental design scenario; and

describe and calculate, using scientific notation, how the magnitude of force between two objects depends on their masses and the distance between their centers, and predict the effects on objects in linear and orbiting systems using Newton's law of universal gravitation.

The student knows the nature of forces in the physical world. The student is expected to:

use scientific notation and predict how the magnitude of the electric force between two objects depends on their charges and the distance between their centers using Coulomb's law;

identify and describe examples of electric and magnetic forces and fields in everyday life such as generators, motors, and transformers;

investigate and describe conservation of charge during the processes of induction, conduction, and polarization using different materials such as electroscopes, balloons, rods, fur, silk, and Van de Graaf generators;

analyze, design, and construct series and parallel circuits using schematics and materials such as switches, wires, resistors, lightbulbs, batteries, voltmeters, and ammeters; and

calculate current through, potential difference across, resistance of, and power used by electric circuit elements connected in both series and parallel circuits using Ohm's law.

The student knows that changes occur within a physical system and applies the laws of conservation of energy and momentum. The student is expected to:

calculate and explain work and power in one dimension and identify when work is and is not being done by or on a system;

investigate and calculate mechanical, kinetic, and potential energy of a system;

apply the concept of conservation of energy using the work-energy theorem, energy diagrams, and energy transformation equations, including transformations between kinetic, potential, and thermal energy;

calculate and describe the impulse and momentum of objects in physical systems such as automobile safety features, athletics, and rockets; and

analyze the conservation of momentum qualitatively in inelastic and elastic collisions in one dimension using models, diagrams, and simulations.

The student knows the characteristics and behavior of waves. The student is expected to:

examine and describe simple harmonic motion such as masses on springs and pendulums and wave energy propagation in various types of media such as surface waves on a body of water and pulses in ropes;

compare the characteristics of transverse and longitudinal waves, including electromagnetic and sound waves;

investigate and analyze characteristics of waves, including velocity, frequency, amplitude, and wavelength, and calculate using the relationships between wave speed, frequency, and wavelength;

investigate behaviors of waves, including reflection, refraction, diffraction, interference, standing wave, the Doppler effect and polarization and superposition; and

compare the different applications of the electromagnetic spectrum, including radio telescopes, microwaves, and x-rays;

investigate the emission spectra produced by various atoms and explain the relationship to the electromagnetic spectrum; and

describe and predict image formation as a consequence of reflection from a plane mirror and refraction through a thin convex lens.

The student knows examples of quantum phenomena and their applications. The student is expected to:

describe the photoelectric effect and emission spectra produced by various atoms and how both are explained by the photon model for light;

investigate Malus's Law and describe examples of applications of wave polarization, including 3-D movie glasses and LCD computer screens;

compare and explain how superposition of quantum states is related to the wave-particle duality nature of light; and

give examples of applications of quantum phenomena, including the Heisenberg uncertainty principle, quantum computing, and cybersecurity.

The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to explain phenomena or design solutions using appropriate tools and models. The student is expected to:

ask questions and define problems related to specialized topics of study based on observations or information from text, phenomena, models, or investigations;

apply science practices related to specialized topics of study to plan and conduct investigations or use engineering practices to design solutions to problems;

use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

use tools appropriate to the specialized topic of study;

collect quantitative data using the International System of Units (SI) or qualitative data as evidence as appropriate to the specialized topic of study;

organize quantitative or qualitative data using representations appropriate to the specialized topic of study such as scatter plots, line graphs, bar graphs, charts, data tables, diagrams, scientific drawings, and student-prepared models;

develop and use models to represent phenomena, systems, processes, or solutions to problems as appropriate to the specialized topic of study; and

distinguish among scientific hypotheses, theories, and laws as appropriate to the specialized topic of study.

The student analyzes and interprets data to derive meaning, identify features and patterns, and discover relationships or correlations to develop evidence-based arguments or evaluate designs. The student is expected to:

identify advantages and limitations of models such as their size, scale, properties, and materials as appropriate to the specialized topic of study;

analyze data appropriate to the specialized topic of study by identifying significant statistical features, patterns, sources of error, and limitations;

use mathematical calculations to assess quantitative relationships in data as appropriate to the specialized topic of study; and

evaluate experimental or engineering designs as appropriate to the specialized topic of study.

The student develops evidence-based explanations and communicates findings, conclusions, or proposed solutions. The student is expected to:

develop explanations or propose solutions supported by data and models consistent with scientific ideas, principles, and theories as appropriate to the specialized topic of study;

communicate explanations or solutions individually and collaboratively in a variety of settings and formats as appropriate to the specialized topic of study; and

engage respectfully in scientific argumentation using applied scientific explanations and empirical evidence as appropriate to the specialized topic of study.

The student knows the contributions of scientists and recognizes the importance of scientific research and innovation on society. The student is expected to:

analyze, evaluate, and critique scientific explanations and solutions by using empirical evidence, logical reasoning, and experimental or observational testing as appropriate to the specialized topic of study, so as to encourage critical thinking by the student;

relate the impact of past and current research on scientific thought and society, including research methodology, cost-benefit analysis, and contributions of diverse scientists as appropriate to the specialized topic of study; and

research and explore resources such as museums, libraries, professional organizations, private companies, online platforms, and mentors employed in a science, technology, engineering, and mathematics (STEM) field in order to investigate STEM careers as appropriate to the specialized topic of study.