STANDARD 1—Analysis, Inquiry, and Design
Students will use mathematical analysis, scientific inquiry, and engineering design, as appropriate, to pose
questions, seek answers, and develop solutions.
Key Idea 1:
The central purpose of scientific inquiry is to develop explanations of natural phenomena
in a continuing, creative process.
S1.1 Formulate questions independently with the aid of references appropriate for
guiding the search for explanations of everyday observations.
S1.1a formulate questions about natural phenomena
S1.1b identify appropriate references to investigate a question
S1.1c refine and clarify questions so that they are subject to scientific investigation
S1.2 Construct explanations independently for natural phenomena, especially by
proposing preliminary visual models of phenomena.
S1.2a independently formulate a hypothesis
S1.2b propose a model of a natural phenomenon
S1.2c differentiate among observations, inferences, predictions, and explanations
S1.3 Represent, present, and defend their proposed explanations of everyday observations
so that they can be understood and assessed by others.
S1.4 Seek to clarify, to assess critically, and to reconcile with their own thinking the
ideas presented by others, including peers, teachers, authors, and scientists.
Key Idea 2:
Beyond the use of reasoning and consensus, scientific inquiry involves the testing of proposed
explanations involving the use of conventional techniques and procedures and usually
requiring considerable ingenuity.
S2.1 Use conventional techniques and those of their own design to make further observations
and refine their explanations, guided by a need for more information.
S2.1a demonstrate appropriate safety techniques
S2.1b conduct an experiment designed by others
S2.1c design and conduct an experiment to test a hypothesis
S2.1d use appropriate tools and conventional techniques to solve problems
about the natural world, including: measuring, observing, describing, classifying, and sequencing
S2.2 Develop, present, and defend formal research proposals for testing their own
explanations of common phenomena, including ways of obtaining needed observations
and ways of conducting simple controlled experiments.
S2.2a include appropriate safety procedures
S2.2b design scientific investigations (e.g., observing, describing, and comparing;
collecting samples; seeking more information, conducting a controlled
experiment; discovering new objects or phenomena; making models)
S2.2c design a simple controlled experiment
S2.2d identify independent variables (manipulated), dependent variables
(responding), and constants in a simple controlled experiment
S2.2e choose appropriate sample size and number of trials
S2.3 Carry out their research proposals, recording observations and measurements
(e.g., lab notes, audiotape, computer disk, videotape) to help assess the explanation.
S2.3a use appropriate safety procedures
S2.3b conduct a scientific investigation
S2.3c collect quantitative and qualitative data
Key Idea 3:
The observations made while testing proposed explanations, when analyzed using conventional
and invented methods, provide new insights into phenomena.
S3.1 Design charts, tables, graphs, and other representations of observations in conventional
and creative ways to help them address their research question or hypothesis.
S3.1a organize results, using appropriate graphs, diagrams, data tables, and
other models to show relationships
S3.1b generate and use scales, create legends, and appropriately label axes
S3.2 Interpret the organized data to answer the research question or hypothesis and to
gain insight into the problem.
S3.2a accurately describe the procedures used and the data gathered
S3.2b identify sources of error and the limitations of data collected
S3.2c evaluate the original hypothesis in light of the data
S3.2d formulate and defend explanations and conclusions as they relate to
S3.2e form and defend a logical argument about cause-and-effect relationships
in an investigation
S3.2f make predictions based on experimental data
S3.2g suggest improvements and recommendations for further studying
S3.2h use and interpret graphs and data tables
S3.3 Modify their personal understanding of phenomena based on evaluation of their
STANDARD 4- The Living Environment
Students will understand and apply scientific concepts, principles, and theories pertaining to the physical
setting and living environment and recognize the historical development of ideas in science.
Key Idea 1:
Living things are both similar to and different from each other and from nonliving things.
Introduction: Living things are similar to each other yet different from nonliving things. The cell is a basic unit of
structure and function of living things (cell theory). For all living things, life activities are accomplished at the cellular
level. Human beings are an interactive organization of cells, tissues, organs, and systems. Viruses lack cellular
organization. Compare and contrast the parts of plants, animals, and one-celled organisms.
1.1a Living things are composed of cells. Cells provide structure and carry on major
functions to sustain life. Cells are usually microscopic in size.
1.1b The way in which cells function is similar in all living things. Cells grow and
divide, producing more cells. Cells take in nutrients, which they use to provide energy
for the work that cells do and to make the materials that a cell or an organism needs.
1.1c Most cells have cell membranes, genetic material, and cytoplasm. Some cells have
a cell wall and/or chloroplasts. Many cells have a nucleus.
1.1d Some organisms are single cells; others, including humans, are multicellular.
1.1e Cells are organized for more effective functioning in multicellular organisms.
Levels of organization for structure and function of a multicellular organism include
cells, tissues, organs, and organ systems.
1.1f Many plants have roots, stems, leaves, and reproductive structures. These organized
groups of tissues are responsible for a plantÕs life activities.
1.1g Multicellular animals often have similar organs and specialized systems for carrying
out major life activities.
1.1h Living things are classified by shared characteristics on the cellular and organism
level. In classifying organisms, biologists consider details of internal and external structures.
Biological classification systems are arranged from general (kingdom) to specific
1.2a Each system is composed of organs and tissues which perform specific functions
and interact with each other, e.g., digestion, gas exchange, excretion, circulation, locomotion,
control, coordination, reproduction, and protection from disease.
1.2b Tissues, organs, and organ systems help to provide all cells with nutrients, oxygen,
and waste removal.
1.2c The digestive system consists of organs that are responsible for the mechanical and
chemical breakdown of food. The breakdown process results in molecules that can be
absorbed and transported to cells.
1.2d During respiration, cells use oxygen to release the energy stored in food. The respiratory
system supplies oxygen and removes carbon dioxide (gas exchange).
1.2e The excretory system functions in the disposal of dissolved waste molecules, the
elimination of liquid and gaseous wastes, and the removal of excess heat energy.
1.2f The circulatory system moves substances to and from cells, where they are needed
or produced, responding to changing demands.
1.2g Locomotion, necessary to escape danger, obtain food and shelter, and reproduce, is
accomplished by the interaction of the skeletal and muscular systems, and coordinated
by the nervous system.
1.2h The nervous and endocrine systems interact to control and coordinate the bodyÕs
responses to changes in the environment, and to regulate growth, development, and
reproduction. Hormones are chemicals produced by the endocrine system; hormones
regulate many body functions.
1.2i The male and female reproductive systems are responsible for producing sex cells
necessary for the production of offspring.
1.2j Disease breaks down the structures or functions of an organism. Some diseases are
the result of failures of the system. Other diseases are the result of damage by infection
from other organisms (germ theory). Specialized cells protect the body from infectious
disease. The chemicals they produce identify and destroy microbes that enter the body.
Key Idea 2:
Organisms inherit genetic information in a variety of ways that result in continuity of structure and function
between parents and offspring.
Introduction: Every organism requires a set of instructions for specifying its traits. This information is found in the
genes of cells. As organisms reproduce, these instructions are passed from one generation to the next.
Describe sexual and asexual mechanisms for passing genetic materials from generation to
2.1a Hereditary information is contained in genes. Genes are composed of DNA that
makes up the chromosomes of cells.
2.1b Each gene carries a single unit of information. Asingle inherited trait of an individual
can be determined by one pair or by many pairs of genes. A human cell contains
thousands of different genes.
2.1c Each human cell contains a copy of all the genes needed to produce a human being.
2.1d In asexual reproduction, all the genes come from a single parent. Asexually produced
offspring are genetically identical to the parent.
2.1e In sexual reproduction typically half of the genes come from each parent. Sexually
produced offspring are not identical to either parent.
2.2a In all organisms, genetic traits are passed on from generation to generation.
2.2b Some genes are dominant and some are recessive. Some traits are inherited by
mechanisms other than dominance and recessiveness.
2.2c The probability of traits being expressed can be determined using models of
genetic inheritance. Some models of prediction are pedigree charts and Punnett squares.
Key Idea 3:
Individual organisms and species change over time.
Introduction: Evolution is the change in a species over time. Millions of diverse species are alive today. Generally
this diversity of species developed through gradual processes of change occurring over many generations. Species
acquire many of their unique characteristics through biological adaptation, which involves the selection of naturally
occurring variations in populations (natural selection). Biological adaptations are differences in structures,
behaviors, or physiology that enhance survival and reproductive success in a particular environment.
Describe sources of variation in organisms and their structures and relate the variations to
3.1a The processes of sexual reproduction and mutation have given rise to a variety of
traits within a species.
3.1b Changes in environmental conditions can affect the survival of individual organisms
with a particular trait. Small differences between parents and offspring can accumulate
in successive generations so that descendants are very different from their ancestors.
Individual organisms with certain traits are more likely to survive and have
offspring than individuals without those traits.
3.1c Human activities such as selective breeding and advances in genetic engineering
may affect the variations of species.
3.2a In all environments, organisms with similar needs may compete with one another
3.2b Extinction of a species occurs when the environment changes and the adaptive
characteristics of a species are insufficient to permit its survival. Extinction of species is
common. Fossils are evidence that a great variety of species existed in the past.
3.2c Many thousands of layers of sedimentary rock provide evidence for the long history
of Earth and for the long history of changing lifeforms whose remains are found in
the rocks. Recently deposited rock layers are more likely to contain fossils resembling
3.2d Although the time needed for change in a species is usually great, some species of
insects and bacteria have undergone significant change in just a few years.
Key Idea 4:
The continuity of life is sustained through reproduction and development.
Introduction: The survival of a species depends on the ability of a living organism to produce offspring. Living
things go through a life cycle involving both reproductive and developmental stages. Development follows an
orderly sequence of events. Observe and describe the variations in reproductive patterns of organisms, including asexual
and sexual reproduction.
4.1a Some organisms reproduce asexually. Other organisms reproduce sexually. Some
organisms can reproduce both sexually and asexually.
4.1b There are many methods of asexual reproduction, including division of a cell into
two cells, or separation of part of an animal or plant from the parent, resulting in the
growth of another individual.
4.1c Methods of sexual reproduction depend upon the species. All methods involve the
merging of sex cells to begin the development of a new individual. In many species,
including plants and humans, eggs and sperm are produced.
4.1d Fertilization and/or development in organisms may be internal or external.
Explain the role of sperm and egg cells in sexual reproduction.
4.2a The male sex cell is the sperm. The female sex cell is the egg. The fertilization of an
egg by a sperm results in a fertilized egg.
4.2b In sexual reproduction, sperm and egg each carry one-half of the genetic information
for the new individual. Therefore, the fertilized egg contains genetic information
from each parent.
4.3a Multicellular organisms exhibit complex changes in development, which begin
after fertilization. The fertilized egg undergoes numerous cellular divisions that will
result in a multicellular organism, with each cell having identical genetic information.
4.3b In humans, the fertilized egg grows into tissue which develops into organs and
organ systems before birth.
4.3c Various body structures and functions change as an organism goes through its life
4.3d Patterns of development vary among animals. In some species the young resemble
the adult, while in others they do not. Some insects and amphibians undergo metamorphosis
as they mature.
4.3e Patterns of development vary among plants. In seed-bearing plants, seeds contain
stored food for early development. Their later development into adulthood is characterized
by varying patterns of growth from species to species.
4.3f As an individual organism ages, various body structures and functions change.
4.4a In multicellular organisms, cell division is responsible for growth, maintenance,
and repair. In some one-celled organisms, cell division is a method of asexual
4.4b In one type of cell division, chromosomes are duplicated and then separated into
two identical and complete sets to be passed to each of the two resulting cells. In this
type of cell division, the hereditary information is identical in all the cells that result.
4.4c Another type of cell division accounts for the production of egg and sperm cells in
sexually reproducing organisms. The eggs and sperm resulting from this type of cell
division contain one-half of the hereditary information.
4.4d Cancers are a result of abnormal cell division.
Key Idea 5:
Organisms maintain a dynamic equilibrium that sustains life.
Introduction: All organisms must be able to obtain and use resources, grow, reproduce, and maintain stable internal
conditions while living in a constantly changing external environment. Organisms respond to internal or
environmental stimuli. Compare the way a variety of living specimens carry out basic life functions and maintain
5.1a Animals and plants have a great variety of body plans and internal structures that
contribute to their ability to maintain a balanced condition.
5.1b An organismÕs overall body plan and its environment determine the way that the
organism carries out the life processes.
5.1c All organisms require energy to survive. The amount of energy needed and the
method for obtaining this energy vary among cells. Some cells use oxygen to release the
energy stored in food.
5.1d The methods for obtaining nutrients vary among organisms. Producers, such as
green plants, use light energy to make their food. Consumers, such as animals, take in
5.1e Herbivores obtain energy from plants. Carnivores obtain energy from animals.
Omnivores obtain energy from both plants and animals. Decomposers, such as bacteria
and fungi, obtain energy by consuming wastes and/or dead organisms.
5.1f Regulation of an organisms internal environment involves sensing the internal
environment and changing physiological activities to keep conditions within the range
required for survival. Regulation includes a variety of nervous and hormonal feedback
5.1g The survival of an organism depends on its ability to sense and respond to its
5.2a Food provides molecules that serve as fuel and building material for all organisms.
All living things, including plants, must release energy from their food, using it to carry
on their life processes.
5.2b Foods contain a variety of substances, which include carbohydrates, fats, vitamins,
proteins, minerals, and water. Each substance is vital to the survival of the organism.
5.2c Metabolism is the sum of all chemical reactions in an organism. Metabolism can be
influenced by hormones, exercise, diet, and aging.
5.2d Energy in foods is measured in Calories. The total caloric value of each type of
food varies. The number of Calories a person requires varies from person to person.
5.2e In order to maintain a balanced state, all organisms have a minimum daily intake
of each type of nutrient based on species, size, age, sex, activity, etc. An imbalance in any
of the nutrients might result in weight gain, weight loss, or a diseased state.
5.2f Contraction of infectious disease, and personal behaviors such as use of toxic substances
and some dietary habits, may interfere with oneÕs dynamic equilibrium. During
pregnancy these conditions may also affect the development of the child. Some effects of
these conditions are immediate; others may not appear for many years.
Key Idea 6:
Plants and animals depend on each other and their physical environment.
Introduction: An environmentally aware citizen should have an understanding of the natural world. All organisms
interact with one another and are dependent upon their physical environment. Energy and matter flow from one
organism to another. Matter is recycled in ecosystems. Energy enters ecosystems as sunlight, and is eventually lost
from the community to the environment, mostly as heat. Describe the flow of energy and matter through food chains and food webs.
6.1a Energy flows through ecosystems in one direction, usually from the Sun, through
producers to consumers and then to decomposers. This process may be visualized with
food chains or energy pyramids.
6.1b Food webs identify feeding relationships among producers, consumers, and
decomposers in an ecosystem.
6.1c Matter is transferred from one organism to another and between organisms and
their physical environment. Water, nitrogen, carbon dioxide, and oxygen are examples
of substances cycled between the living and nonliving environment.
6.2a Photosynthesis is carried on by green plants and other organisms containing
chlorophyll. In this process, the SunÕs energy is converted into and stored as chemical
energy in the form of a sugar. The quantity of sugar molecules increases in green plants
during photosynthesis in the presence of sunlight.
6.2b The major source of atmospheric oxygen is photosynthesis. Carbon dioxide is
removed from the atmosphere and oxygen is released during photosynthesis.
6.2c Green plants are the producers of food which is used directly or indirectly by
Key Idea 7:
Human decisions and activities have had a profound impact on the physical and living environment.
Introduction: The number of organisms an ecosystem can support depends on the resources available and physical
factors: quantity of light, air, and water; range of temperatures; soil composition. To ensure the survival of our
planet, people have a responsibility to consider the impact of their actions on the environment. Describe how living things, including humans, depend upon the living and nonliving environment for their survival.
7.1a A population consists of all individuals of a species that are found together at a
given place and time. Populations living in one place form a community. The community
and the physical factors with which it interacts compose an ecosystem.
7.1b Given adequate resources and no disease or predators, populations (including
humans) increase. Lack of resources, habitat destruction, and other factors such as predation
and climate limit the growth of certain populations in the ecosystem.
7.1c In all environments, organisms interact with one another in many ways.
Relationships among organisms may be competitive, harmful, or beneficial. Some
species have adapted to be dependent upon each other with the result that neither could
survive without the other.
7.1d Some microorganisms are essential to the survival of other living things.
7.1e The environment may contain dangerous levels of substances (pollutants) that are
harmful to organisms. Therefore, the good health of environments and individuals
requires the monitoring of soil, air, and water, and taking steps to keep them safe.
7.2a In ecosystems, balance is the result of interactions between community members
and their environment.
7.2b The environment may be altered through the activities of organisms. Alterations
are sometimes abrupt. Some species may replace others over time, resulting in longterm
gradual changes (ecological succession).
7.2c Overpopulation by any species impacts the environment due to the increased use
of resources. Human activities can bring about environmental degradation through
resource acquisition, urban growth, land-use decisions, waste disposal, etc.
7.2d Since the Industrial Revolution, human activities have resulted in major pollution
of air, water, and soil. Pollution has cumulative ecological effects such as acid rain,
global warming, or ozone depletion. The survival of living things on our planet depends
on the conservation and protection of Earth's resources.
STANDARD 4- The Physical Setting
Students will understand and apply scientific concepts, principles, and theories pertaining to the physical
setting and living environment and recognize the historical development of ideas in science.
Key Idea 1:
The Earth and celestial phenomena can be described by principles of relative motion and perspective.
The universe is comprised of a wide array of objects, a few of which can be seen by the unaided eye. Others can
only be observed with scientific instruments. These celestial objects, distinct from Earth, are in motion relative to
Earth and each other. Measurements of these motions vary with the perspective of the observer. Cyclical changes
on Earth are caused by interactions among objects in the universe. Explain daily, monthly, and seasonal changes on Earth.
1.1a Earth's Sun is an average-sized star. The Sun is more than a million times greater
in volume than Earth.
1.1b Other stars are like the Sun but are so far away that they look like points of light.
Distances between stars are vast compared to distances within our solar system.
1.1c The Sun and the planets that revolve around it are the major bodies in the solar system.
Other members include comets, moons, and asteroids. EarthÕs orbit is nearly circular.
1.1d Gravity is the force that keeps planets in orbit around the Sun and the Moon in
orbit around the Earth.
1.1e Most objects in the solar system have a regular and predictable motion. These
motions explain such phenomena as a day, a year, phases of the Moon, eclipses, tides,
meteor showers, and comets.
1.1f The latitude/longitude coordinate system and our system of time are based on
1.1g Moons are seen by reflected light. Our Moon orbits Earth, while Earth orbits the
Sun. The MoonÕs phases as observed from Earth are the result of seeing different portions
of the lighted area of the MoonÕs surface. The phases repeat in a cyclic pattern in
about one month.
1.1h The apparent motions of the Sun, Moon, planets, and stars across the sky can be
explained by EarthÕs rotation and revolution. EarthÕs rotation causes the length of one
day to be approximately 24 hours. This rotation also causes the Sun and Moon to appear
to rise along the eastern horizon and to set along the western horizon. EarthÕs revolution
around the Sun defines the length of the year as 365 1/4 days.
1.1i The tilt of EarthÕs axis of rotation and the revolution of Earth around the Sun cause
seasons on Earth. The length of daylight varies depending on latitude and season.
1.1j The shape of Earth, the other planets, and stars is nearly spherical.
Key Idea 2:
Many of the phenomena that we observe on Earth involve interactions among components of air, water, and
land. Students should develop an understanding of Earth as a set of closely coupled systems. The concept of systems
provides a framework in which students can investigate three major interacting components: lithosphere, hydrosphere,
and atmosphere. Processes act within and among the three components on a wide range of time scales to bring about continuous change in Earth's crust, oceans, and atmosphere. Explain how the atmosphere (air), hydrosphere (water), and lithosphere (land) interact, evolve, and change.
2.1a Nearly all the atmosphere is confined to a thin shell surrounding Earth. The atmosphere
is a mixture of gases, including nitrogen and oxygen with small amounts of water
vapor, carbon dioxide, and other trace gases. The atmosphere is stratified into layers,
each having distinct properties. Nearly all weather occurs in the lowest layer of the
2.1b As altitude increases, air pressure decreases.
2.1c The rock at EarthÕs surface forms a nearly continuous shell around Earth called the
2.1d The majority of the lithosphere is covered by a relatively thin layer of water called
2.1e Rocks are composed of minerals. Only a few rock-forming minerals make up most
of the rocks of Earth. Minerals are identified on the basis of physical properties such as
streak, hardness, and reaction to acid.
2.1f Fossils are usually found in sedimentary rocks. Fossils can be used to study past
climates and environments.
2.1g The dynamic processes that wear away EarthÕs surface include weathering and
2.1h The process of weathering breaks down rocks to form sediment. Soil consists of
sediment, organic material, water, and air.
2.1i Erosion is the transport of sediment. Gravity is the driving force behind erosion.
Gravity can act directly or through agents such as moving water, wind, and glaciers.
2.1j Water circulates through the atmosphere, lithosphere, and hydrosphere in what is
known as the water cycle.
2.2a The interior of Earth is hot. Heat flow and movement of material within Earth
cause sections of EarthÕs crust to move. This may result in earthquakes, volcanic
eruption, and the creation of mountains and ocean basins.
2.2b Analysis of earthquake wave data (vibrational disturbances) leads to the conclusion
that there are layers within Earth. These layersÑthe crust, mantle, outer core, and
inner coreÑhave distinct properties.
2.2c Folded, tilted, faulted, and displaced rock layers suggest past crustal movement.
2.2d Continents fitting together like puzzle parts and fossil correlations provided initial
evidence that continents were once together.
2.2e The Theory of Plate Tectonics explains how the ÒsolidÓ lithosphere consists of a
series of plates that ÒfloatÓ on the partially molten section of the mantle. Convection
cells within the mantle may be the driving force for the movement of the plates.
2.2f Plates may collide, move apart, or slide past one another. Most volcanic activity
and mountain building occur at the boundaries of these plates, often resulting in earthquakes.
2.2g Rocks are classified according to their method of formation. The three classes of
rocks are sedimentary, metamorphic, and igneous. Most rocks show characteristics that
give clues to their formation conditions.
2.2h The rock cycle model shows how types of rock or rock material may be transformed
from one type of rock to another.
2.2i Weather describes the conditions of the atmosphere at a given location for a short
period of time.
2.2j Climate is the characteristic weather that prevails from season to season and year
2.2k The uneven heating of EarthÕs surface is the cause of weather.
2.2l Air masses form when air remains nearly stationary over a large section of EarthÕs
surface and takes on the conditions of temperature and humidity from that location.
2.2m Most local weather condition changes are caused by movement of air masses.
2.2n The movement of air masses is determined by prevailing winds and upper air currents.
2.2o Fronts are boundaries between air masses. Precipitation is likely to occur at these
2.2p High-pressure systems generally bring fair weather. Low-pressure systems usually
bring cloudy, unstable conditions. The general movement of highs and lows is from
west to east across the United States.
2.2q Hazardous weather conditions include thunderstorms, tornadoes, hurricanes, ice
storms, and blizzards. Humans can prepare for and respond to these conditions if given
2.2r Substances enter the atmosphere naturally and from human activity. Some of these
substances include dust from volcanic eruptions and greenhouse gases such as carbon
dioxide, methane, and water vapor. These substances can affect weather, climate, and
Key Idea 3:
Matter is made up of particles whose properties determine the observable characteristics of matter and its reactivity.
Objects in the universe are composed of matter. Matter is anything that takes up space and has mass. Matter is classified
as a substance or a mixture of substances. Knowledge of the structure of matter is essential to studentsÕ understanding
of the living and physical environments. Matter is composed of elements which are made of small particles
called atoms. All living and nonliving material is composed of these elements or combinations of these elements.
Observe and describe properties of materials, such as density, conductivity, and solubility.
3.1a Substances have characteristic properties. Some of these properties include color,
odor, phase at room temperature, density, solubility, heat and electrical conductivity,
hardness, and boiling and freezing points.
3.1b Solubility can be affected by the nature of the solute and solvent, temperature, and
pressure. The rate of solution can be affected by the size of the particles, stirring,
temperature, and the amount of solute already dissolved.
3.1c The motion of particles helps to explain the phases (states) of matter as well as
changes from one phase to another. The phase in which matter exists depends on the
attractive forces among its particles.
3.1d Gases have neither a determined shape nor a definite volume. Gases assume the
shape and volume of a closed container.
3.1e A liquid has definite volume, but takes the shape of a container.
3.1f A solid has definite shape and volume. Particles resist a change in position.
3.1g Characteristic properties can be used to identify different materials, and separate a
mixture of substances into its components. For example, iron can be removed from a
mixture by means of a magnet. An insoluble substance can be separated from a soluble
substance by such processes as filtration, settling, and evaporation.
3.1h Density can be described as the amount of matter that is in a given amount of
space. If two objects have equal volume, but one has more mass, the one with more
mass is denser.
3.1i Buoyancy is determined by comparative densities.
3.2a During a physical change a substance keeps its chemical composition and properties.
Examples of physical changes include freezing, melting, condensation, boiling,
evaporation, tearing, and crushing.
3.2b Mixtures are physical combinations of materials and can be separated by physical
3.2c During a chemical change, substances react in characteristic ways to form new
substances with different physical and chemical properties. Examples of chemical
changes include burning of wood, cooking of an egg, rusting of iron, and souring of
3.2d Substances are often placed in categories if they react in similar ways. Examples
include metals, nonmetals, and noble gases.
3.2e The Law of Conservation of Mass states that during an ordinary chemical reaction
matter cannot be created or destroyed. In chemical reactions, the total mass of the
reactants equals the total mass of the products.
3.3a All matter is made up of atoms. Atoms are far too small to see with a light
3.3b Atoms and molecules are perpetually in motion. The greater the temperature, the
greater the motion.
3.3c Atoms may join together in well-defined molecules or may be arranged in regular
3.3d Interactions among atoms and/or molecules result in chemical reactions.
3.3e The atoms of any one element are different from the atoms of other elements.
3.3f There are more than 100 elements. Elements combine in a multitude of ways to
produce compounds that account for all living and nonliving substances. Few elements
are found in their pure form.
3.3g The periodic table is one useful model for classifying elements. The periodic table
can be used to predict properties of elements (metals, nonmetals, noble gases).
Key Idea 4:
Energy exists in many forms, and when these forms change energy is conserved.
Introduction: An underlying principle of all energy use is the Law of Conservation of Energy. Simply stated, energy
cannot be created or destroyed.
Energy can be transformed, one form to another. These transformations produce heat energy. Heat is a calculated
value which includes the temperature of the material, the mass of the material, and the type of the material.
Temperature is a direct measurement of the average kinetic energy of the particles in a sample of material. It should
be noted that temperature is not a measurement of heat.
4.1a The Sun is a major source of energy for Earth. Other sources of energy include
nuclear and geothermal energy.
4.1b Fossil fuels contain stored solar energy and are considered nonrenewable resources.
They are a major source of energy in the United States. Solar energy, wind, moving water,
and biomass are some examples of renewable energy resources.
4.1c Most activities in everyday life involve one form of energy being transformed into
another. For example, the chemical energy in gasoline is transformed into mechanical
energy in an automobile engine. Energy, in the form of heat, is almost always one of the
products of energy transformations.
4.1d Different forms of energy include heat, light, electrical, mechanical, sound, nuclear,
and chemical. Energy is transformed in many ways.
4.1e Energy can be considered to be either kinetic energy, which is the energy of
motion, or potential energy, which depends on relative position.
4.2a Heat moves in predictable ways, flowing from warmer objects to cooler ones, until
both reach the same temperature.
4.2b Heat can be transferred through matter by the collisions of atoms and/or molecules
(conduction) or through space (radiation). In a liquid or gas, currents will facilitate
the transfer of heat (convection).
4.2c During a phase change, heat energy is absorbed or released. Energy is absorbed
when a solid changes to a liquid and when a liquid changes to a gas. Energy is released
when a gas changes to a liquid and when a liquid changes to a solid.
4.2d Most substances expand when heated and contract when cooled. Water is an
exception, expanding when changing to ice.
4.2e Temperature affects the solubility of some substances in water.
4.3a In chemical reactions, energy is transferred into or out of a system. Light, electricity,
or mechanical motion may be involved in such transfers in addition to heat.
4.4a Different forms of electromagnetic energy have different wavelengths. Some examples
of electromagnetic energy are microwaves, infrared light, visible light, ultraviolet
light, X-rays, and gamma rays.
4.4b Light passes through some materials, sometimes refracting in the process.
Materials absorb and reflect light, and may transmit light. To see an object, light from
that object, emitted by or reflected from it, must enter the eye.
4.4c Vibrations in materials set up wave-like disturbances that spread away from the
source. Sound waves are an example. Vibrational waves move at different speeds in
different materials. Sound cannot travel in a vacuum.
4.4d Electrical energy can be produced from a variety of energy sources and can be
transformed into almost any other form of energy.
4.4e Electrical circuits provide a means of transferring electrical energy.
4.4f Without touching them, material that has been electrically charged attracts
uncharged material, and may either attract or repel other charged material.
4.4g Without direct contact, a magnet attracts certain materials and either attracts or
repels other magnets. The attractive force of a magnet is greatest at its poles.
4.5a Energy cannot be created or destroyed, but only changed from one form into
4.5b Energy can change from one form to another, although in the process some energy
is always converted to heat. Some systems transform energy with less loss of heat than
Key Idea 5:
Energy and matter interact through forces that result in changes in motion.
Introduction: Examples of objects in motion can be seen all around us. These motions result from an interaction of
energy and matter. This interaction creates forces (pushes and pulls) that produce predictable patterns of change.
Common forces would include gravity, magnetism, and electricity. Friction is a force that should always be considered
in a discussion of motion.
When the forces acting on an object are unbalanced, changes in that objectÕs motion occur. The changes could
include a change in speed or a change in direction. When the forces are balanced, the motion of that object will
remain unchanged. Understanding the laws that govern motion allows us to predict these changes in motion.
Describe different patterns of motion of objects.
5.1a The motion of an object is always judged with respect to some other object or
point. The idea of absolute motion or rest is misleading.
5.1b The motion of an object can be described by its position, direction of motion, and speed.
5.1c An objectÕs motion is the result of the combined effect of all forces acting on the
object. A moving object that is not subjected to a force will continue to move at a constant
speed in a straight line. An object at rest will remain at rest.
5.1d Force is directly related to an objectÕs mass and acceleration. The greater the force,
the greater the change in motion.
5.1e For every action there is an equal and opposite reaction.
5.2a Every object exerts gravitational force on every other object. Gravitational force
depends on how much mass the objects have and on how far apart they are. Gravity is
one of the forces acting on orbiting objects and projectiles.
5.2b Electric currents and magnets can exert a force on each other.
5.2c Machines transfer mechanical energy from one object to another.
5.2d Friction is a force that opposes motion.
5.2e A machine can be made more efficient by reducing friction. Some common ways of
reducing friction include lubricating or waxing surfaces.
5.2f Machines can change the direction or amount of force, or the distance or speed of
force required to do work.
5.2g Simple machines include a lever, a pulley, a wheel and axle, and an inclined plane.
A complex machine uses a combination of interacting simple machines, e.g., a bicycle.