The Nature of Science
Students further their scientific understanding of
the natural world through investigations, experiences, and readings. They design solutions to practical problems by using
a variety of scientific methodologies.
The Scientific View of the World
Recognize and explain that when similar investigations give different results, the scientific challenge is to judge
whether the differences are trivial or significant, which often takes further studies to decide.
Explain that what people expect to observe often affects what they actually do observe and provide an example of a
solution to this problem.
Explain why it is important in science to keep honest, clear, and accurate records.
Describe that different explanations can be given for the same evidence, and it is not always possible to tell which
one is correct without further inquiry.
The Scientific Enterprise
Identify some important contributions to the advancement of science, mathematics, and technology that have been made
by different kinds of people, in different cultures, at different times.
Provide examples of people who overcame bias and/or limited opportunities in education and employment to excel in the
fields of science.
Technology and Science
Explain how engineers, architects, and others who engage in design and technology use scientific knowledge to solve
Explain that technologies often have drawbacks as well as benefits. Consider a technology, such as the use of pesticides,
which helps some organisms but may hurt others, either deliberately or inadvertently.
Explain how societies influence what types of technology are developed and used in fields such as agriculture, manufacturing,
sanitation, medicine, warfare, transportation, information processing, and communication.
Identify ways that technology has strongly influenced the course of history and continues to do so.
Illustrate how numbers can be represented using sequences of only two symbols, such as 1 and 0 or on and off, and how
that affects the storage of information in our society.
Students use instruments and tools to measure, calculate,
and organize data. They frame arguments in quantitative terms when possible. They question claims and understand that findings
may be interpreted in more than one acceptable way.
Computation and Estimation
Find what percentage one number is of another and figure any percentage of any number.
Use formulas to calculate the circumferences and areas* of rectangles, triangles, and circles, and the volumes* of
Decide what degree of precision is adequate, based on the degree of precision of the original data, and round off the
result of calculator operations to significant figures* that reasonably reflect those of the inputs.
Express numbers like 100, 1,000, and 1,000,000 as powers of 10.
Estimate probabilities of outcomes in familiar situations, on the basis of history or the number of possible outcomes.
area: a measure of the size of a two-dimensional region
volume: a measure of the size of a three-dimensional object
significant figures: digits that appropriately express the precision of a measurement or quantity derived mathematically
from one or more measurements
Manipulation and Observation
Read analog and digital meters on instruments used to make direct measurements of length, volume, weight, elapsed time,
rates, or temperatures, and choose appropriate units.
Incorporate circle charts, bar and line graphs, diagrams, scatterplots*, and symbols into writing, such as lab or research
reports, to serve as evidence for claims and/or conclusions.
scatterplot: a coordinate graph showing ordered pairs of data
Critical Response Skills
Question claims based on vague attributes, such as “Leading doctors say ... ,” or on statements made by
celebrities or others outside the area of their particular expertise.
The Physical Setting
Students collect and organize data to identify relationships
between physical objects, events, and processes. They use logical reasoning to question their own ideas as new information
challenges their conceptions of the natural world.
Recognize and describe that the sun is a medium-sized star located near the edge of a disk-shaped galaxy of stars and
that the universe contains many billions of galaxies and each galaxy contains many billions of stars.
Recognize and describe that the sun is many thousands of times closer to Earth than any other star, allowing light
from the sun to reach Earth in a few minutes. Note that this may be compared to time spans of longer than a year for all other
Earth and the Processes That Shape It
Describe how climates sometimes have changed abruptly in the past as a result of changes in Earth’s crust, such
as volcanic eruptions or impacts of huge rocks from space.
Explain how heat flow and movement of material within Earth causes earthquakes and volcanic eruptions and creates mountains
and ocean basins.
Recognize and explain that heat energy carried by ocean currents has a strong influence on climate around the world.
Describe how gas and dust from large volcanoes can change the atmosphere.
Give examples of some changes in Earth’s surface that are abrupt, such as earthquakes and volcanic eruptions,
and some changes that happen very slowly, such as uplift and wearing down of mountains and the action of glaciers.
Describe how sediments of sand and smaller particles, sometimes containing the remains of organisms, are gradually
buried and are cemented together by dissolved minerals to form solid rock again.
Explain that sedimentary rock*, when buried deep enough, may be reformed by pressure and heat, perhaps melting and
recrystallizing into different kinds of rock. Describe that these reformed rock layers may be forced up again to become land
surface and even mountains, and subsequently erode.
Explain how the thousands of layers of sedimentary rock can confirm the long history of the changing surface of Earth
and the changing life forms whose remains are found in successive layers, although the youngest layers are not always found
on top, because of folding, breaking, and uplifting of layers.
sedimentary rock: rock formed by compression of successive layers of silt or other small particles
Matter* and Energy*
Explain that the sun loses energy by emitting light. Note that only a tiny fraction of that light reaches Earth. Understand
that the sun’s energy arrives as light with a wide range of wavelengths*, consisting of visible light and infrared*
and ultraviolet radiation*.
Investigate how the temperature* and acidity* of a solution influences reaction rates, such as those resulting in food
Explain that many substances dissolve in water. Understand that the presence of these substances often affects the
rates of reactions that are occurring in the water as compared to the same reactions occurring in the water in the absence
of the substances.
Explain that energy in the form of heat is almost always one of the products of an energy trans-formation, such as
in the examples of exploding stars, biological growth, the operation of machines, and the motion of people.
Describe how electrical energy can be produced from a variety of energy sources and can be transformed into almost
any other form of energy, such as light or heat.
Recognize and explain that different ways of obtaining, transforming, and distributing energy have different environmental
matter: anything that has mass* and takes up space
mass: a measure of how much matter is in an object
energy: what is needed to make things move
wavelength: the distance between two consecutive, similar points on a wave*
wave: a traveling disturbance that carries energy from one place to another
infrared radiation: electromagnetic radiation having wavelengths longer than those of red light but shorter than microwaves
ultraviolet radiation: electromagnetic radiation having wavelengths shorter than those of visible light but longer
than those of x-rays
temperature: a measure of average heat energy that can be measured using a thermometer
acidity: a measure of the hydrogen ion concentration in a chemical system
Forces of Nature
Investigate that an unbalanced force, acting on an object, changes its speed* or path of motion or both, and know that
if the force always acts toward the same center as the object moves, the object’s path may curve into an orbit around
Describe that light waves, sound waves, and other waves move at different speeds in different materials.
Explain that human eyes respond to a narrow range of wavelengths of the electromagnetic spectrum*.
Describe that something can be “seen” when light waves emitted or reflected by it enter the eye just as
something can be “heard” when sound waves from it enter the ear.
speed: the rate per unit time at which an object moves
electromagnetic spectrum: the arrangement of electromagnetic waves* in order of wavelength and frequency*
electromagnetic waves: a combination of electric and magnetic fields, each regenerating the other, that carry energy
through space – light and radio waves are examples
frequency: the number of waves that pass a certain point per unit time
The Living Environment
Students begin to trace the flow of matter and energy
through ecosystems. They recognize the funda-mental difference between plants and animals and understand its basis at the
cellular level. Students distinguish species, particularly through an examination of internal structures and functions. They
use microscopes to observe cells and recognize that cells function in similar ways in all organisms.
Diversity of Life
Explain that similarities among organisms are found in external and internal anatomical features, including specific
characteristics at the cellular level, such as the number of chromosomes*. Understand that these similarities are used to
classify organisms since they may be used to infer the degree of relatedness among organisms.
Describe that all organisms, including the human species*, are part of and depend on two main interconnected global
food webs*, the ocean food web and the land food web.
Explain how, in sexual reproduction, a single specialized cell from a female merges with a specialized cell from a
male and this fertilized egg carries genetic information from each parent and multiplies to form the complete organism.
Explain that cells continually divide to make more cells for growth and repair and that various organs and tissues
function to serve the needs of cells for food, air, and waste removal.
Explain that the basic functions of organisms, such as extracting energy from food and getting rid of wastes, are carried
out within the cell and understand that the way in which cells function is similar in all organisms.
chromosomes: a cell structure that contains DNA, a chemical which directs the activities of a cell and passes on the
traits of a cell to new cells
species: a category of biological classification that is comprised of organisms sufficiently and closely related as
to be potentially able to mate with one another
food web: all food chains* in an ecosystem that are connected
food chain: food and energy links between different plants, animals, and other organisms in an ecosystem*
ecosystem: a group of organisms in an area that interact with one another, together with their nonliving environment
Interdependence of Life and Evolution
Explain how food provides the fuel and the building material for all organisms.
Describe how plants use the energy from light to make sugars from carbon dioxide and water to produce food that can
be used immediately or stored for later use.
Describe how organisms that eat plants break down the plant structures to produce the materials and energy that they
need to survive, and in turn, how they are consumed by other organisms.
Understand and explain that as any population of organisms grows, it is held in check by one or more environmental
factors. These factors could result in depletion of food or nesting sites and/or increased loss to increased numbers of predators
or parasites. Give examples of some consequences of this.
Describe how technologies having to do with food production, sanitation, and disease prevention have dramatically changed
how people live and work and have resulted in changes in factors that affect the growth of human population.
Explain that the amount of food energy (calories) a person requires varies with body weight, age, sex, activity level,
and natural body efficiency. Understand that regular exercise is important to maintain a healthy heart/lung system, good muscle
tone, and strong bone structure.
Explain that viruses, bacteria, fungi, and parasites may infect the human body and interfere with normal body functions.
Recognize that a person can catch a cold many times because there are many varieties of cold viruses that cause similar symptoms.
Explain that white blood cells engulf invaders or produce antibodies that attack invaders or mark the invaders for
killing by other white blood cells. Know that the antibodies produced will remain and can fight off subsequent invaders of
the same kind.
Explain that the environment may contain dangerous levels of substances that are harmful to human beings. Understand,
therefore, that the good health of individuals requires monitoring the soil, air, and water as well as taking steps to keep
Students apply mathematics in scientific contexts.
They use mathematical ideas, such as relations between operations, symbols, statistical relationships, and the use of logical
reasoning, in the representation and synthesis of data.
Demonstrate how a number line can be extended on the other side of zero to represent negative numbers and give examples
of instances where this is useful.
Shapes and Symbolic Relationships
Illustrate how lines can be parallel, perpendicular, or oblique.
Demonstrate how the scale chosen for a graph or drawing determines its interpretation.
Reasoning and Uncertainty
Describe that the larger the sample, the more accurately it represents the whole. Understand, however, that any sample
can be poorly chosen and this will make it unrepresentative of the whole.
Students gain understanding of how the scientific
enterprise operates through examples of historical events. Through the study of these events, they understand that new ideas
are limited by the context in which they are conceived, are often rejected by the scientific establishment, sometimes spring
from unexpected findings, and grow or transform slowly through the contributions of many different investigators.
Understand and explain that throughout history, people have created explanations for disease. Note that some held that
disease had spiritual causes, but that the most persistent biological theory over the centuries was that illness resulted
from an imbalance in the body fluids. Realize that the introduction of germ theory by Louis Pasteur and others in the nineteenth
century led to the modern understanding of how many diseases are caused by microorganisms, such as bacteria, viruses, yeasts,
Understand and explain that Louis Pasteur wanted to find out what caused milk and wine to spoil. Note that he demonstrated
that spoilage and fermentation* occur when microorganisms enter from the air, multiply rapidly, and produce waste products,
with some desirable results, such as carbon dioxide in bread dough, and some undesirable, such as acetic acid in wine. Understand
that after showing that spoilage could be avoided by keeping germs out or by destroying them with heat, Pasteur investigated
animal diseases and showed that microorganisms were involved in many of them. Also note that other investigators later showed
that specific kinds of germs caused specific diseases.
Understand and explain that Louis Pasteur found that infection by disease organisms (germs) caused the body to build
up an immunity against subsequent infection by the same organisms. Realize that Pasteur then demonstrated more widely what
Edward Jenner had shown for smallpox without understanding the underlying mechanism: that it was possible to produce vaccines
that would induce the body to build immunity to a disease without actually causing the disease itself.
Understand and describe that changes in health practices have resulted from the acceptance of the germ theory of disease.
Realize that before germ theory, illness was treated by appeals to supernatural powers or by attempts to adjust body fluids
through induced vomiting or bleeding. Note that the modern approach emphasizes sanitation, the safe handling of food and water,
the pasteurization of milk, quarantine, and aseptic surgical techniques to keep germs out of the body; vaccinations to strengthen
the body’s immune system against subsequent infection by the same kind of microorganisms; and antibiotics and other
chemicals and processes to destroy microorganisms.
fermentation: the chemical decomposition of an organic substance
Students analyze the relationships within systems.
They investigate how different models can represent the same data, rates of change, cyclic changes, and changes that counterbalance
Explain that the output from one part of a system, which can include material, energy, or information, can become the
input to other parts and this feedback can serve to control what goes on in the system as a whole.
Models and Scale
Use different models to represent the same thing, noting that the kind of model and its complexity should depend on
Constancy and Change
Describe how physical and biological systems tend to change until they reach equilibrium and remain that way unless
their surroundings change.
Use symbolic equations to show how the quantity of something changes over time or in response to changes in other quantities.