Draft: May 7, 2007
The PA Science Benchmarks are presented in two sections:
Section I: Discipline-specific Science Learning Essentials:
1 Earth & Space Science
2
3
4
Life Science
Physical Science
Chemical Science.
Section II: Interdisciplinary Science Learning Essentials:
1
2
Process Skills: Inquiry & Unifying Themes
Quantitative Skills
3
4
Technology Skills
Science History and Society
1 EARTH AND SPACE SCIENCE
1.1 The Universe
1.1.1 Observe and explain the Universe and its evolution using parts of the electromagnetic spectrum.
1.1.2 Recognize how the "big bang" theory places the origin of the universe to be approximately 14 billion years ago and how the redshift and cosmic background radiation provide supporting evidence.
1.1.3 Explain how large objects such as galaxies, stars and planetary systems can be formed from the gravitational attraction of dust and gas.
1.1.4 Compare and contrast the stars and galaxies by their size, various properties and how they are distributed in the universe.
1.1.5 Describe how the development of elements can be traced to the generation of energy in stars.
1.2 Earth and Its Solar System
1.2.1 Describe the objects in our solar system including the Sun, the Moon, the planets and their moons, and smaller objects.
1.2.2 Explain how the orbit and rotational axes of the Sun/Earth/Moon system and the motions of these objects give rise to days, nights, phases of the Moon, and eclipses.
1

1.2.3 Describe the planetary orbits and explain how gravity is responsible for that motion.
1.2.4 Identify observational evidence that supports the model of a heliocentric solar system.
1.3
Earth Systems and Energy Transformation
1.3.1 Describe a change that has occurred in one of the Earth systems that is a consequence, at least in part, of human actions.
1.3.2 Describe the energy balance at the Earth’s surface in terms of energy sinks and energy sources.
1.3.3 Identify situations within the Earth and space environment that illustrate the various types of energy transport mechanisms.
1.3.4 Identify common emitters and common absorbers of ultraviolet, visible and infrared radiation.
1.3.5 Explain how the Earth’s magnetic field protects the Earth from the flow of interstellar particles.
1.4 Earth’s Ocean – Atmosphere System
1.4.1 Explain how gravity gives rise to the tides and how the rotation of the Earth relative to the Moon’s position is responsible for the semidiurnal periodicity.
1.4.2 Describe the interaction between large-scale temperature changes in the atmosphere and ocean temperature and ocean currents.
1.4.3 Describe how satellite-based infrared observations of the atmosphere and oceans can be used to obtain temperature measurements.
1.4.4 Recognize that the ocean covers approximately 70% of the Earth, and that it has an interconnected circulation system powered by wind and water density differences.
1.4.5 Interpret the meaning of sea-level and explain how geological movements and large-scale temperature changes can impact sea level.
1.5 Earth’s Atmosphere - Weather and Climate
1.5.1 Use common instruments used for directly observing the atmosphere via surface or balloon ascents.
1.5.2 Recognize how air density tends to decrease with height and that almost all of the mass of the atmosphere is in a region that is very shallow region where weather and climate occur.
1.5.3 Compare and contrast between clouds, common types of precipitation, and air.
1.5.4 Describe the role of the Sun in causing weather.
2

1.5.5 Describe the relationship between the inclination of the incoming solar radiation, the latitude, and the temperature of a region.
1.5.6 Describe four mechanisms by which air cools/warms and apply these mechanisms to explain phenomena associated with cooling/warming in the atmosphere and the ocean.
1.5.7 Explain how cooling of water vapor can lead to its condensation and predict situations where clouds and/or precipitation can form based upon the potential for cooling.
1.5.8 Describe and distinguish between the following severe weather events: thunderstorms, winter storms and nor’easters, hurricanes, and tornados.
1.5.9 Utilize observable characteristics of clouds and surface observations with weather maps and weather data to predict regional weather events and the potential for severe weather.
1.6 Global Warming and Climate Change
1.6.1 Explain how a change in minor components of the atmosphere can ultimately lead to changes in the Earth’s surface temperature.
1.6.2 Describe and interpret the evidence and for short-term and long-term global warming and cooling.
1.7 Earth Structures and Features
1.7.1 Recognize that the Earth is not uniform and can be classified into layers based on different criteria.
1.7.2 Explain how seismic data are used to reveal Earth’s interior structure and to locate earthquake epicenters.
1.7.3 Describe the mechanism for propelling tectonic plates across the Earth's surface and the resulting geologic features. Explain why plate tectonics is not common to all the objects in the Solar System.
1.7.4 Explain how known decay rates of radioactive isotopes in rocks can be used to measure the time since formation and that geologic time can be estimated by observing rock sequences and using fossils.
1.7.5 Recognize that rocks and minerals can be classified by their origin and formation, igneous, sedimentary, and metamorphic, and that the process of formation leads to similar physical properties within groups.
1.7.6 Describe and evaluate the processes involved in the creation of geologic feature. Utilize geologic and topographic maps to identify these features.
1.7.7 Describe situations of physical and chemical weathering and explain how these processes lead to erosion and the formation of soils and sediments.
1.7.8 Describe the scales frequently used for measuring the strength or damage associated with a natural event or phenomenon.
1.7.9 Describe strategies for preparing for and recovering from natural disasters.
3

2 LIFE SCIENCE
2.1 The Chemistry of Life
2.1.1 At the molecular level, biology is based on three-dimensional interactions of macromolecules which are primarily composed of C, H, N, O, P, and S.
2.1.2 Describe the basic molecular structures and primary functions of the four major categories of organic macromolecules in plants and animals: carbohydrates, lipids, proteins, nucleic acids.
2.1.3 Explain the role of enzymes as catalysts that lower the activation energy of biochemical reactions.
2.1.4 Life has a very narrow range of acceptable conditions in which to flourish.
Identify factors, such as pH and temperature, which have an effect on biochemical reactions.
2.2 Cell Biology
2.2.1 Relate cell parts/organelles to their functions. Explain the role of cell membranes as a highly selective barrier and the membrane-associated processes of diffusion, osmosis, facilitated diffusion and active transport.
2.2.2 Compare and contrast, at the cellular level, the general structures and degrees of complexity prokaryotes and eukaryotes.
2.2.3 Describe the characteristics of organisms that used are to classify them into domains and/or kingdoms.
2.2.4 Identify the reactants, products, and basic purposes of photosynthesis and cellular respiration. Explain the interrelated nature of photosynthesis and cellular respiration in the cells of photosynthetic organisms.
2.2.5 Explain the important role that ATP serves in metabolism.
2.2.6 Describe cell replication and the process of mitosis. Explain the role of mitosis in the formation of new cells, and its importance in maintaining chromosome number during asexual reproduction.
2.2.7 Describe how the process of meiosis results in the formation of haploid cells.
Explain the importance of this process in sexual reproduction, and how gametes form diploid zygotes in the process of fertilization.
2.2.8 Compare and contrast a virus and a cell in terms of genetic material and reproduction.
2.3. Genetics and Molecular Biology
2.3.1 Describe DNA structure, the processes involved in replication, and the causes of mutational events.
2.3.2 Explain the basic processes of transcription and translation, and how they result in the expression of genes. Distinguish among the end products of replication, transcription, and translation.
4

2.3.3 Explain how mutations in the DNA sequence of a gene may or may not result in phenotypic changes in an organism. Explain how mutations in gametes may result in phenotypic changes in the offspring.
2.3.4 Distinguish among observed inheritance patterns resulting from dominant, recessive, codominant, or sex-linked genetic traits.
2.3.5 Describe how Mendel’s laws of segregation can be predicted with a Punnett
Square and through patterns of inheritance.
2.3.6 Explain the basic concepts supporting commonly used molecular biology techniques: DNA fingerprinting and Polymerase Chain Reaction (PCR).
2.4 Evolution and Biodiversity
2.4.1 Explain how evolution is demonstrated by evidence from the fossil record, comparative anatomy and embryology, genetics, molecular biology, and examples of natural selection. Use this evidence can to demonstrate and classify evolutionary relationships in a hierarchical manner.
2.4.2 Explain how DNA sequences are used to define relationships that may or may not be apparent through phenotypical comparisons.
2.4.3 Explain how evolution, through natural selection can result in changes in plant and animal biodiversity within a population. Discuss factors that play a role in natural selection.
2.4.4 Provide evidence that evolution is not a static process and is occurring in organisms today. Changes in viruses, antibiotic resistance of bacteria, genes from genetically modified plants appearing in native plants, resistance of insects to pesticides.
2.4.5 Explore the theory of evolution based on the mechanism of natural selection as proposed by Darwin and Wallace. Explore additional the scientific principles beyond those of Darwin and Wallace supporting the theory of evolution.
2.4.6 Place the major animal phyla on a phylogenetic tree to demonstrate logical evolutionary relationships.
2.5 Organismic Biology
2.5.1 Describe the various forms of asexual and sexual reproductions demonstrated by the members of the animal and plants kingdom.
2.5.2 Discuss the organs and organelles responsible for the transport of water and food through plants.
2.6. Mammalian Anatomy and Physiology
2.6.1 Describe the key features of the major anatomical and physiological systems of the body, including the digestive, circulatory, excretory, immune, respiratory, nervous, musculoskeletal, and reproductive systems.
5

2.6.2 Recognize that cells signal each other through a wide variety of pathways to coordinate homeostasis.
2.7 Ecology
2.7.1 Explain the energy flow within a food web: identify and distinguish producers, consumers, and decomposers.
2.7.2 Explain the water, carbon, oxygen and nitrogen cycles.
2.7.3 Describe the positive and negative roles that the microorganisms play in their environments.
2.7.4 Examine and explain the path of a recyclable material from collection to waste, reuse or recycling identifying the market forces.
2.7.5 Explain renewable and nonrenewable resources and their impact on the environment.
2.7.6 Identify environmental health issues; visible and invisible pollutants and explain their effects on human health.
2.7.7 Describe the ecosystems of watersheds and wetlands and the effects of human activities on these ecosystems.
3 PHYSICAL SCIENCE
3.1 Motion and Forces
3.1.1 Describe the difference between scalar and vector quantities.
3.1.2 Demonstrate a conceptual and quantitative understanding of force as defined by Newton’s Laws of Motion.
3.1.3 Demonstrate a conceptual and quantitative understanding of balanced forces using examples of solids, liquids and gases.
3.1.4 Explain and compute the forces acting on a body in motion at constant linear acceleration or constant circular acceleration.
3.2 Conservation of Energy
3.2.1 Describe and compute gravitational and elastic potential energies in relevant situations.
3.2.2 Describe both conceptually and quantitatively how work can be expressed as a change in mechanical energy.
3.2.3 Demonstrate an understanding of the law of conservation of energy in mechanical systems in relevant situations.
3.3 Conservation of Momentum
3.3.1 Demonstrate an understanding of elastic and inelastic collisions.
6

3.3.2 Compute the motions of bodies undergoing elastic collisions that obey the law of conservation of linear momentum.
3.3.3 Demonstrate a conceptual understanding of the law of conservation angular momentum for relevant situations.
3.4 Heat and Heat Transfer
3.4.1 Explain how heat and temperature are different concepts.
3.4.2 Describe the relationship between average molecular kinetic energy and temperature.
3.4.3 Explain qualitatively how heat energy is transferred by the processes of convection, conduction, and radiation and provide relevant examples.
3.4.4 Explain how heat energy will move from an object at higher temperature to one at lower temperature until equilibrium is reached using knowledge of specific heat capacities.
3.5 Waves
3.5.1 Describe the measurable properties of standing and traveling waves and explain the relationships among the properties.
3.5.2 Recognize that the media and states of matter affect the transmission velocity of a mechanical wave.
3.5.3 Describe the differences between mechanical waves and electromagnetic waves.
3.5.4 Describe the Doppler Effect on the properties of mechanical and electromagnetic waves.
3.5.5 Apply concepts of the electromagnetic spectrum to understand common applications in communication and medical technologies.
3.6 Electromagnetism
3.6.1 Explain why gravitational forces play a more important role in macroscopic systems than electrical forces.
3.6.2 Demonstrate a conceptual understanding of the differences between insulators and conductors.
3.6.3 Demonstrate a conceptual and quantitative understanding of how current, voltage and resistance are interrelated using Ohm’s Law, and solve practical problems using common voltmeters.
3.6.4 Describe conceptually how moving electric charges create magnetic forces and moving magnets produce electric fields, and demonstrate the application of these forces using electric motors, generators, and other technologies.
7

3.7 Atomic and Nuclear Physics
3.7.1 Describe the properties of protons, neutrons, and electrons, and how these particles contribute to the physical properties of atoms.
3.7.2 Demonstrate a conceptual understanding that electron orbital transitions are the atomic basis of light absorption and emission.
3.7.3 Describe and contrast Bohr’s model and the modern model of the atom.
3.7.4 Describe different nuclear reactions and explain industrial, medical, and military applications that are based on these reactions.
3.7.5 Explain the concept of radioactive half-life of decay and its applications in science and medicine.
4 CHEMICAL SCIENCE
4.1 The Macroscopic Realm of Matter
4.1.1 Explain and apply common properties of matter such as density, conductivity, corrosiveness, reactivity, solubility, melting point and boiling point to identify, synthesize and separate compounds.
4.1.2 Interpret and apply warning label information found on laboratory, industrial, agricultural, and household chemicals.
4.2 Gases
4.2.1 Explain and apply the basic relationships between the physical properties of gases including the Ideal Gas Law, Charles’ Law and Boyle’s Law.
4.2.2 Use chemical reactions to prepare and observe the properties of common gases.
4.2.3 Explain and apply the concept that chemical reactions obey the Law of
Conservation of Mass.
4.3 An Atomic Perspective, Energy, and Phase Change
4.3.1 Identify the main points and limitations of Dalton’s Atomic Theory, and its usefulness in accounting for the Kinetic Molecular Theory.
4.3.2 Explain the Kinetic Molecular Theory as it pertains to differences in solids, liquids, and gases.
4.3.4 Explain the molecular nature of a closed system in terms of energy, phase changes, and the establishment of dynamic equilibria.
4.4 Atomic Structure, Organizing the Elements, and Periodicity
4.4.1 Describe the properties of protons, neutrons, and electrons, and how these particles contribute to chemical properties of atoms.
8

4.4.2 Use the periodic table to predict the properties of known and unknown elements by identifying trends in physical properties and characteristics such as size, reactivity, electronegativity, ionization energy and electron affinity.
4.5 Chemical Bonding, Molecular Shape and Interactions
4.5.1 Describe the differences between covalent and ionic compounds and the atomic properties and processes producing these types of bonds using Lewis structures.
4.5.2 Determine the formulas for both simple covalent and ionic compounds based on the positions of the combining elements on the periodic table.
4.5.3 Predict the shapes and polarity of simple molecules through the use of
Valence Shell Electron Repulsion (VSEPR) Theory.
4.5.4 Identify crystal structures for simple ionic compounds.
4.5.5 Distinguish between chemical bonds and intermolecular forces; and describe the effects they may have on the properties of a substance or solution.
4.6 Acids and Bases
4.6.1 Identify examples of acids and bases and describe one or more models such as Arrhenius, Brönsted-Lowry, or Lewis models that explain the properties of each of these two classes.
4.6.2 Explain the meaning and applications of the pH scale, and connect pH values to the reactivity of acids and bases.
4.6.3 Identify examples of weak and strong acids and bases and know how each should used and handled in common household and workplace situations.
4.6.4 Use the concept of pH to explain buffers.
4.7 Chemical Reactions and Stoichiometry
4.7.1 Interpret the symbols used in chemical reactions such as subscripts, coefficients, states of matter, heat, equilibrium, etc.
4.7.2 Apply the Law of Definite Proportions to determine empirical formulas.
4.7.3 Perform basic stoichiometric calculations and unit conversions to determine the concentrations of solutions and predict reaction yields.
4.7.4 Explain how and why chemical reactions must be balanced.
4.7.5 Identify basic types of chemical reactions such as decomposition, single replacement and identify likely products of simple chemical reactions.
4.7.6 Explain the molecular processes involved in common acid-base neutralization reactions and common oxidation-reduction reactions.
4.7.7 Understand the difference between thermodynamic and kinetic descriptions of a chemical reaction.
9

4.8.7 Explain Le Chậtelier’s principle applies to dynamic equilibrium of chemical reactions.
1 PROCESS SKILLS: SCIENTIFIC INQUIRY & UNIFYING PRINCIPLES
Inquiry is a creative process guided by a set of logical principles which scientists and engineers use to investigate questions and solve problems, extending the scope of human knowledge about natural and human-made worlds.
1.1 Scientists and engineers typically ask questions about phenomena that cannot be explained with the current state of scientific or engineering knowledge.
A. Unexplained phenomena can take many forms (new observations, unexplained experimental results, unexpected mathematical results, etc.)
1) The implications of mathematical results have relevance in science and engineering because mathematics is the natural language of these fields of study.
B. Scientific and Engineering questions fall into basic categories: What is it, how does it work, how did it come to be this way, how can I improve it, or can I create something which will…?
1.2 Scientific or engineering knowledge starts with inferences or predictions drawn between unexplained phenomena and potential explanations.
A. Inference attempts to establish a cause and effect relationship between phenomena and potential explanations.
B. Prediction attempts to identify repeated patterns in phenomena.
C. There is no single path by which to infer an explanation from a phenomenon.
1) To arrive at an inference, individuals may draw on prior knowledge, theory, induction, deduction or a combination of these.
2) Inference typically follows many design cycles before the proposed explanation seems a strong candidate for explaining the phenomena. At this point, the proposed explanation becomes a hypothesis. a) Each design cycle can follow a number of steps: preparation, incubation, orientation, illumination and verification.
3) A hypothesis is an informed statement of what might be true.
10

1.3 Different kinds of Scientific or Engineering questions suggest different kinds of investigations.
A. Scientists and engineers test hypotheses with investigations.
B. An informative investigation is designed to distinguish between hypotheses.
1) Every investigation or observation is based on samples from the larger universe of observations. Therefore, observations without interpretation or prior knowledge are meaningless.
2) Many observations are susceptible to multiple alternative logical interpretations or hypotheses.
C. A well-planned investigation produces evidence designed to make one interpretation or hypothesis likely and to exclude as many alternative interpretations or hypotheses as possible.
1.4 When possible, investigations should have controls.
A. An investigation often takes the form of an experiment where things are manipulated. Things that influence an experiment’s outcome are known as variables.
B. Variables subject to experimental manipulation are known as independent variables. Experimental variables affected by independent variables are known as dependent variables.
C. To demonstrate cause and effect in a hypothesis, an investigation must provide strong evidence. For example, a phenomenon that occurs after a certain treatment is given to a subject, and that phenomenon does not occur in the absence of the treatment is strong evidence.
D. Evidence gathered from investigations results must be widely disseminated, peer reviewed and replicated in order to be considered part of scientific or engineering knowledge.
1.5 A scientific theory is a mature body of interconnected hypotheses or mathematics based on reasoning and backed by strong experimental evidence that explains a variety of observations.
A. Theories should make predictions about investigations not yet performed.
B. Theories predict what is possible and what is impossible. As a result there is often a reciprocal causation between theory and investigation.
C. Theories are not static. All theories are subject to new investigations and observations which may result in parts of the theory being modified, discarded or added.
11

2
1.6. Laws are scientific hypothesis that have universal application and are often stated in the language of mathematics.
A. Theories are developed as an explanation of laws. Laws do no explain theories.
QUANTITATIVE SCIENCE SKILLS
2.1 Generate an appropriate model such as an equation, scale, table, graph or diagram to solve a problem.
2.2 Determine or describe or use relationships between variables or objects in mathematical situations.
2.3 Use scientific abbreviations, symbols units and scales in relevant contexts.
2.4 Perform unit conversions within and between common systems of measurements.
2.5 Detect patterns in data, describe or summarize data trends, and interpolate or extrapolate from data or given information.
2.6 Perform basic statistical procedures to analyze the center and spread of data.
3 TECHNOLOGY SKILLS
3.1 Use diagrams or models to demonstrate an understanding of scientific concepts, relationships, processes or systems.
3.2 Use scientific instruments to detect, observe, measure or characterize the microscopic or macroscopic properties of matter, force or energy.
3.3 Understand that all scientific instruments have inherent limitations, affecting their measurement range, accuracy and precision.
3.4 Use common computer hardware and software for data manipulations, graphing, and modeling.
3.5 Retrieve applications and data from the Internet for use in scientific problem solving.
3.6 Use and understand common technologies knowing that technologies are constantly changing requiring lifelong learning.
4 SCIENCE HISTORY AND SOCIETY
4.1 Describe landmarks in scientific theories scientific, developments and ideas.
4.2 Describe how scientific knowledge and applications have changed over time.
4.3 Describe how the work of science relies on basic human qualities, such as reasoning, insight, energy, skill and creativity —as well as on scientific habits
12

of mind, such as intellectual honesty, tolerance of ambiguity, skepticism, and openness to new ideas.
4.4 Describe important limitations of scientific knowledge.
4.5 Describe the diversity of career options in Science, Technology, Engineering, and Math (STEM) fields and the associated categories of learning essentials that are pre-requisite to growth in those fields.
13