Life Science
National
Science Standards-- National Science Content Standards, 9-12,
for each topic in biology are given where they apply. Those 9-12
content standards not addressed in these pages include:
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Multicellular animals have nervous systems that
generate behavior. Nervous systems are formed from specialized cells that
conduct signals rapidly through the long cell extensions that make up nerves.
The nerve cells communicate with each other by secreting specific excitatory
and inhibitory molecules. In sense organs, specialized cells detect light,
sound, and specific chemicals and enable animals to monitor what is going
on in the world around them.
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Organisms have behavioral responses to internal
changes and to external stimuli. Responses to external stimuli can result
from interactions with the organism's own species and others, as well as
environmental changes; these responses either can be innate or learned.
The broad patterns of behavior exhibited by animals have evolved to ensure
reproductive success. Animals often live in unpredictable environments,
and so their behavior must be flexible enough to deal with uncertainty
and change. Plants also respond to stimuli.
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Behavioral biology has implications for humans,
as it provides links to psychology, sociology, and anthropology.
The
National
Science Standards that address the Study of Life, Chemistry and science
teaching in general are:
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Identify questions and concepts that guide scientific
investigations.
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Scientists usually inquire about how physical,
living, or designed systems function. Conceptual principles and knowledge
guide scientific inquiries. Historical and current scientific knowledge
influence the design and interpretation of investigations and the evaluation
of proposed explanations made by other scientists.
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Design and conduct scientific investigations.
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Scientists conduct investigations for a wide
variety of reasons. For example, they may wish to discover new aspects
of the natural world, explain recently observed phenomena, or test the
conclusions of prior investigations or the predictions of current theories.
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Use technology and mathematics to improve investigations
and communications.
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Scientists rely on technology to enhance the
gathering and manipulation of data. New techniques and tools provide new
evidence to guide inquiry and new methods to gather data, thereby contributing
to the advance of science. The accuracy and precision of the data, and
therefore the quality of the exploration, depends on the technology used.
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Mathematics is essential in scientific inquiry.
Mathematical tools and models guide and improve the posing of questions,
gathering data, constructing explanations and communicating results.
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Formulate and revise scientific explanations
and models using logic and evidence.
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Scientific explanations must adhere to criteria
such as: a proposed explanation must be logically consistent; it must abide
by the rules of evidence; it must be open to questions and possible modification;
and it must be based on historical and current scientific knowledge.
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Recognize and analyze alternative explanations
and models
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Communicate and defend a scientific argument.
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Results of scientific inquiry--new knowledge
and methods--emerge from different types of investigations and public communication
among scientists. In communicating and defending the results of scientific
inquiry, arguments must be logical and demonstrate connections between
natural phenomena, investigations, and the historical body of scientific
knowledge. In addition, the methods and procedures that scientists used
to obtain evidence must be clearly reported to enhance opportunities for
further investigation.
These
are the National Science Content Standards for THE CELL that also
apply to the Chemistry of Life:
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Inside the cell is a concentrated mixture of
thousands of different molecules which form a variety of specialized structures
that carry out such cell functions as energy production, transport of molecules,
waste disposal, synthesis of new molecules, and the storage of genetic
material.
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Most cell functions involve chemical reactions.
Food molecules taken into cells react to provide the chemical constituents
needed to synthesize other molecules. Both breakdown and synthesis are
made possible by a large set of protein catalysts, called enzymes. The
breakdown of some of the food molecules enables the cell to store energy
in specific chemicals that are used to carry out the many functions of
the cell.
These
are the National Science Content Stardards for THE CELL:
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Cells have particular structures that underlie
their functions. Every cell is surrounded by a membrane that separates
it from the outside world. Inside the cell is a concentrated mixture of
thousands of different molecules which form a variety of specialized structures
that carry out such cell functions as energy production, transport of molecules,
waste disposal, synthesis of new molecules, and the storage of genetic
material. [See Unifying
Concepts and Processes]
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Most cell functions involve chemical reactions.
Food molecules taken into cells react to provide the chemical constituents
needed to synthesize other molecules. Both breakdown and synthesis are
made possible by a large set of protein catalysts, called enzymes. The
breakdown of some of the food molecules enables the cell to store energy
in specific chemicals that are used to carry out the many functions of
the cell.
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Cells store and use information to guide their
functions. The genetic information stored in DNA is used to direct the
synthesis of the thousands of proteins that each cell requires.
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Cell functions are regulated. Regulation occurs
both through changes in the activity of the functions performed by proteins
and through the selective expression of individual genes. This regulation
allows cells to respond to their environment and to control and coordinate
cell growth and division.
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Plant cells contain chloroplasts, the site of
photosynthesis. Plants and many microorganisms use solar energy to combine
molecules of carbon dioxide and water into complex, energy rich organic
compounds and release oxygen to the environment. This process of photosynthesis
provides a vital connection between the sun and the energy needs of living
systems.
Cells can differentiate, and complex multicellular
organisms are formed as a highly organized arrangement of differentiated
cells. In the development of these multicellular organisms, the progeny
from a single cell form an embryo in which the cells multiply and differentiate
to form the many specialized cells, tissues and organs that comprise the
final organism. This differentiation is regulated through the expression
of different genes.
These
are the National Science Content Stardards for THE CELL and MATTER,
ENERGY, AND ORGANIZATION IN LIVING SYSTEMS that also apply to Cellular
Respiration and Photosynthesis:
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All matter tends toward more disorganized states.
Living systems require a continuous input of energy to maintain their chemical
and physical organizations. With death, and the cessation of energy input,
living systems rapidly disintegrate. [See
Unifying Concepts and Processes]
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Most cell functions involve chemical reactions.
Food molecules taken into cells react to provide the chemical constituents
needed to synthesize other molecules. Both breakdown and synthesis are
made possible by a large set of protein catalysts, called enzymes. The
breakdown of some of the food molecules enables the cell to store energy
in specific chemicals that are used to carry out the many functions of
the cell.
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Plant cells contain chloroplasts, the site of
photosynthesis. Plants and many microorganisms use solar energy to combine
molecules of carbon dioxide and water into complex, energy rich organic
compounds and release oxygen to the environment. This process of photosynthesis
provides a vital connection between the sun and the energy needs of living
systems.
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The energy for life primarily derives from the
sun. Plants capture energy by absorbing light and using it to form strong
(covalent) chemical bonds between the atoms of carbon-containing (organic)
molecules. These molecules can be used to assemble larger molecules with
biological activity (including proteins, DNA, sugars, and fats). In addition,
the energy stored in bonds between the atoms (chemical energy) can be used
as sources of energy for life processes.
The chemical bonds of food molecules contain
energy. Energy is released when the bonds of food molecules are broken
and new compounds with lower energy bonds are formed. Cells usually store
this energy temporarily in phosphate bonds of a small high-energy compound
called ATP.
These
are the National Science Content Stardards for THE CELL and THE
MOLECULAR BASIS OF HEREDITY that also apply to DNA and RNA:
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Cells store and use information to guide their
functions. The genetic information stored in DNA is used to direct the
synthesis of the thousands of proteins that each cell requires.
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In all organisms, the instructions for specifying
the characteristics of the organism are carried in DNA, a large polymer
formed from subunits of four kinds (A, G, C, and T). The chemical and structural
properties of DNA explain how the genetic information that underlies heredity
is both encoded in genes (as a string of molecular "letters") and replicated
(by a templating mechanism). Each DNA molecule in a cell forms a single
chromosome. [See
Content Standard B (grades 9-12)]
Changes in DNA (mutations) occur spontaneously
at low rates. Some of these changes make no difference to the organism,
whereas others can change cells and organisms. Only mutations in germ cells
can create the variation that changes an organism's offspring.
These
are the National Content Stardards for THE CELL and THE MOLECULAR BASIS
OF HEREDITY that also apply to Mitosis and Meiosis:
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Cell functions are regulated. Regulation occurs
both through changes in the activity of the functions performed by proteins
and through the selective expression of individual genes. This regulation
allows cells to respond to their environment and to control and coordinate
cell growth and division.
-
Cells can differentiate, and complex multicellular
organisms are formed as a highly organized arrangement of differentiated
cells. In the development of these multicellular organisms, the progeny
from a single cell form an embryo in which the cells multiply and differentiate
to form the many specialized cells, tissues and organs that comprise the
final organism. This differentiation is regulated through the expression
of different genes.
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Most of the cells in a human contain two copies
of each of 22 different chromosomes. In addition, there is a pair of chromosomes
that determines sex: a female contains two X chromosomes and a male contains
one X and one Y chromosome. Transmission of genetic information to offspring
occurs through egg and sperm cells that contain only one representative
from each chromosome pair. An egg and a sperm unite to form a new individual.
The fact that the human body is formed from cells that contain two copies
of each chromosome--and therefore two copies of each gene--explains many
features of human heredity, such as how variations that are hidden in one
generation can be expressed in the next.
These
are the National Science Content Standards for THE MOLECULAR BASIS
OF HEREDITY:
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In all organisms, the instructions for specifying
the characteristics of the organism are carried in DNA, a large polymer
formed from subunits of four kinds (A, G, C, and T). The chemical and structural
properties of DNA explain how the genetic information that underlies heredity
is both encoded in genes (as a string of molecular "letters") and replicated
(by a templating mechanism). Each DNA molecule in a cell forms a single
chromosome. [See
Content Standard B (grades 9-12)]
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Most of the cells in a human contain two copies
of each of 22 different chromosomes. In addition, there is a pair of chromosomes
that determines sex: a female contains two X chromosomes and a male contains
one X and one Y chromosome. Transmission of genetic information to offspring
occurs through egg and sperm cells that contain only one representative
from each chromosome pair. An egg and a sperm unite to form a new individual.
The fact that the human body is formed from cells that contain two copies
of each chromosome--and therefore two copies of each gene--explains many
features of human heredity, such as how variations that are hidden in one
generation can be expressed in the next.
-
Changes in DNA (mutations) occur spontaneously
at low rates. Some of these changes make no difference to the organism,
whereas others can change cells and organisms. Only mutations in germ cells
can create the variation that changes an organism's offspring.
These
are the National Science Content Standards for BIOLOGICAL EVOLUTION
and THE BEHAVIOR OF ORGANISMS that also apply to Evolution:
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Species evolve over time. Evolution is the consequence
of the interactions of (1) the potential for a species to increase its
numbers, (2) the genetic variability of offspring due to mutation and recombination
of genes, (3) a finite supply of the resources required for life, and (4)
the ensuing selection by the environment of those offspring better able
to survive and leave offspring. [See
Unifying Concepts and Processes]
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The great diversity of organisms is the result
of more than 3.5 billion years of evolution that has filled every available
niche with life forms.
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Natural selection and its evolutionary consequences
provide a scientific explanation for the fossil record of ancient life
forms, as well as for the striking molecular similarities observed among
the diverse species of living organisms.
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The millions of different species of plants,
animals, and microorganisms that live on earth today are related by descent
from common ancestors.
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Biological classifications are based on how
organisms are related. Organisms are classified into a hierarchy of groups
and subgroups based on similarities which reflect their evolutionary relationships.
Species is the most fundamental unit of classification.
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Organisms have behavioral responses to internal
changes and to external stimuli. Responses to external stimuli can result
from interactions with the organism's own species and others, as well as
environmental changes; these responses either can be innate or learned.
The broad patterns of behavior exhibited by animals have evolved to ensure
reproductive success. Animals often live in unpredictable environments,
and so their behavior must be flexible enough to deal with uncertainty
and change. Plants also respond to stimuli.
-
Like other aspects of an organism's biology,
behaviors have evolved through natural selection. Behaviors often have
an adaptive logic when viewed in terms of evolutionary principles.
These
are the National Science Content Standards for BIOLOGICAL EVOLUTION
but also apply to The History of Life:
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Species evolve over time. Evolution is the consequence
of the interactions of (1) the potential for a species to increase its
numbers, (2) the genetic variability of offspring due to mutation and recombination
of genes, (3) a finite supply of the resources required for life, and (4)
the ensuing selection by the environment of those offspring better able
to survive and leave offspring. [See
Unifying Concepts and Processes]
-
The great diversity of organisms is the result
of more than 3.5 billion years of evolution that has filled every available
niche with life forms.
-
Natural selection and its evolutionary consequences
provide a scientific explanation for the fossil record of ancient life
forms, as well as for the striking molecular similarities observed among
the diverse species of living organisms.
-
The millions of different species of plants,
animals, and microorganisms that live on earth today are related by descent
from common ancestors.
This
is the National Science Content Standard for BIOLOGICAL EVOLUTION
that applies to classification:
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Biological classifications are based on how
organisms are related. Organisms are classified into a hierarchy of groups
and subgroups based on similarities which reflect their evolutionary relationships.
Species is the most fundamental unit of classification.
These
are the National Science Content Standards for THE INTERDEPENDENCE
OF ORGANISMS and MATTER, ENERGY, AND ORGANIZATION IN LIVING SYSTEMS that
apply to the Principles of Ecology:
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The atoms and molecules on the earth cycle among
the living and nonliving components of the biosphere.
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Energy flows through ecosystems in one direction,
from photosynthetic organisms to herbivores to carnivores and decomposers.
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Organisms both cooperate and compete in ecosystems.
The interrelationships and interdependencies of these organisms may generate
ecosystems that are stable for hundreds or thousands of years.
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As matter and energy flows through different
levels of organization of living systems--cells, organs, organisms, communities--and
between living systems and the physical environment, chemical elements
are recombined in different ways. Each recombination results in storage
and dissipation of energy into the environment as heat. Matter and energy
are conserved in each change.
These
are the National Science Content Standards for MATTER, ENERGY, AND
ORGANIZATION IN LIVING SYSTEMS that apply to Communities and Biomes:
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The distribution and abundance of organisms
and populations in ecosystems are limited by the availability of matter
and energy and the ability of the ecosystem to recycle materials.
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As matter and energy flows through different
levels of organization of living systems--cells, organs, organisms, communities--and
between living systems and the physical environment, chemical elements
are recombined in different ways. Each recombination results in storage
and dissipation of energy into the environment as heat. Matter and energy
are conserved in each change.
These
are the National Science Content Standards for THE INTERDEPENDENCE
OF ORGANISMS and MATTER, ENERGY, AND ORGANIZATION IN LIVING SYSTEMS that
also apply to Populations:
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Living organisms have the capacity
to produce populations of infinite size, but environments and resources
are finite. This fundamental tension has profound effects on the interactions
between organisms.
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The distribution and abundance
of organisms and populations in ecosystems are limited by the availability
of matter and energy and the ability of the ecosystem to recycle materials.
This
is the National Science Content Standard for THE INTERDEPENDENCE
OF ORGANISMS that applies to the Diversity of Life:
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Human beings live within the world's ecosystems.
Increasingly, humans modify ecosystems as a result of population growth,
technology, and consumption. Human destruction of habitats through direct
harvesting, pollution, atmospheric changes, and other factors is threatening
current global stability, and if not addressed, ecosystems will be irreversibly
affected.
National
Science Teaching Standard-- One segment of National Science Teaching
Standard A states:
Select science content and adapt
and design curricula to meet the interests, knowledge, understanding, abilities,
and experiences of students.
From watching CSI on television and like
shows, students find forensic studies in science interesting and
they can relate the science to their experiences. Relating a holiday
theme to the science also promotes student interest.
NSTA's "SciLinks"
has also created this customized stardard for the study of forensics:
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Science in Personal and Social Perspectives
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Science and technology in society
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Forensics is the use of science and technology
to investigate and establish facts in criminal or civil courts of law
Physical Science
These
are the National Science Content Standards for the PROPERTIES AND
CHANGES OF PROPERTIES IN MATTER, 5-8, that apply to the Study of Matter
are:
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A substance has characteristic properties, such
as density, a boiling point, and solubility, all of which are independent
of the amount of the sample. A mixture of substances often can be separated
into the original substances using one or more of the characteristic properties.
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Substances react chemically in characteristic
ways with other substances to form new substances (compounds) with different
characteristic properties. In chemical reactions, the total mass is conserved.
Substances often are placed in categories or groups if they react in similar
ways; metals is an example of such a group.
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Chemical elements do not break down during normal
laboratory reactions involving such treatments as heating, exposure to
electric current, or reaction with acids. There are more than 100 known
elements that combine in a multitude of ways to produce compounds, which
account for the living and nonliving substances that we encounter.
These
are the National Science Content Standards for the STRUCTURE OF
ATOMS, that apply to The Atom:
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Matter is made of minute particles called atoms,
and atoms are composed of even smaller components. These components have
measurable properties, such as mass and electrical charge. Each atom has
a positively charged nucleus surrounded by negatively charged electrons.
The electric force between the nucleus and electrons holds the atom together.
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The atom's nucleus is composed of protons and
neutrons, which are much more massive than electrons. When an element has
atoms that differ in the number of neutrons, these atoms are called different
isotopes of the element.
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Atoms interact with one another by transferring
or sharing electrons that are furthest from the nucleus. These outer electrons
govern the chemical properties of the element.
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Each kind of atom or molecule can gain or lose
energy only in particular discrete amounts and thus can absorb and emit
light only at wavelengths corresponding to these amounts. These wavelengths
can be used to identify the substance.
These
are the National Science Content Standards for the STRUCTURE AND
PROPERTIES OF MATTER that apply to The Periodic Table:
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An element is composed of a single type of atom.
When elements are listed in order according to the number of protons (called
the atomic number), repeating patterns of physical and chemical properties
identify families of elements with similar properties. This "Periodic Table"
is a consequence of the repeating pattern of outermost electrons and their
permitted energies.
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In some materials, such as metals, electrons
flow easily, whereas in insulating materials such as glass they can hardly
flow at all. Semiconducting materials have intermediate behavior. At low
temperatures some materials become superconductors and offer no resistance
to the flow of electrons.
These
are the National Science Content Standards for the STRUCTURE AND
PROPERTIES OF MATTER that apply to Compounds:
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Atoms interact with one another by transferring
or sharing electrons that are furthest from the nucleus. These outer electrons
govern the chemical properties of the element.
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Bonds between atoms are created when electrons
are paired up by being transferred or shared. A substance composed of a
single kind of atom is called an element. The atoms may be bonded together
into molecules or crystalline solids. A compound is formed when two or
more kinds of atoms bind together chemically.
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The physical properties of compounds reflect
the nature of the interactions among its molecules. These interactions
are determined by the structure of the molecule, including the constituent
atoms and the distances and angles between them.
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Carbon atoms can bond to one another in chains,
rings, and branching networks to form a variety of structures, including
synthetic polymers, oils, and the large molecules essential to life.
These
are the National Science Content Standards for CHEMICAL REACTIONS:
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Chemical reactions occur all around us, for
example in health care, cooking, cosmetics, and automobiles. Complex chemical
reactions involving carbon-based molecules take place constantly in every
cell in our bodies. [See
Content Standard C (grades 9-12) ]
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Chemical reactions may release or consume energy.
Some reactions such as the burning of fossil fuels release large amounts
of energy by losing heat and by emitting light. Light can initiate many
chemical reactions such as photosynthesis and the evolution of urban smog.
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A large number of important reactions involve
the transfer of either electrons (oxidation/reduction reactions) or hydrogen
ions (acid/base reactions) between reacting ions, molecules, or atoms.
In other reactions, chemical bonds are broken by heat or light to form
very reactive radicals with electrons ready to form new bonds. Radical
reactions control many processes such as the presence of ozone and greenhouse
gases in the atmosphere, burning and processing of fossil fuels, the formation
of polymers, and explosions.
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Chemical reactions can take place in time periods
ranging from the few femtoseconds (10-15 seconds) required for an atom
to move a fraction of a chemical bond distance to geologic time scales
of billions of years. Reaction rates depend on how often the reacting atoms
and molecules encounter one another, on the temperature, and on the properties--including
shape--of the reacting species.
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Catalysts, such as metal surfaces, accelerate
chemical reactions. Chemical reactions in living systems are catalyzed
by protein molecules called enzymes.
These
are the National Science Content Standards for the STRUCTURE AND
PROPERTIES OF MATTER and CONSERVATION OF ENERGY AND THE INCREASE IN DISORDER
that apply to Kinetic Theory:
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Solids, liquids, and gases differ in the distances
and angles between molecules or atoms and therefore the energy that binds
them together. In solids the structure is nearly rigid; in liquids molecules
or atoms move around each other but do not move apart; and in gases molecules
or atoms move almost independently of each other and are mostly far apart.
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All energy can be considered to be either kinetic
energy, which is the energy of motion; potential energy, which depends
on relative position; or energy contained by a field, such as electromagnetic
waves.
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Heat consists of random motion and the vibrations
of atoms, molecules, and ions. The higher the temperature, the greater
the atomic or molecular motion.
There
is not perfect fit in the National Science Content Standards for
Gas Laws.
However, NSTA's "SciLinks" has created customized standards
for this content:
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Structure and properties of matter
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The volume of a sample of gas
at constant pressure is directly proportional to the absolute temperature.
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The total pressure in a gas mixture
is the sum of the partial pressures of the individual components, each
behaving as if the other gas were absent.
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Properties and changes of properties
in matter
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Boyle's law states that at a constant
temperature, the volume of a gas increases as the pressure decreases.
There
is not perfect fit in the National Science Content Standards for
Chemical Quantities.
However, NSTA's "SciLinks" has created a customized standard
for this content:
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Structure of atoms
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One mole represents 6.02 X10 23
particles. This is also know as Avogadro's number. (Molecular Mass)
These
are the National Science Content Standards, 5-8, that apply to Water
and Solutions:
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Properties and Changes of Properties
in Matter
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Substances react chemically in characteristic
ways with other substances to form new substances (compounds) with different
characteristic properties.
-
A mixture of substances often can be separated
into the original substances using one or more of the characteristic properties.
-
And NSTA's "SciLinks" has created
this customized stardard:
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Solubility is the measure of the amount of a
solute that will dissolve in a given quantity of solvent at a given temperature.
There
is not perfect fit in the National Science Content Standards for
Acids and Bases.
However, NSTA's "SciLinks" has created a customized standard
for this content:
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Structure and properties of matter
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When acids are dissolved in water,
the hydronium ion concentration of the water increases. Acids taste sour.
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When a base is dissolved in water,
the concentration of the hydroxide ion increases. Bases taste bitter
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Chemical Reactions
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An acid and base neutralize one
another to produce water and a salt.
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pH is the relative concentration
of hydrogen ions in a solution. This value represents the acidity or alkalinity
of the solution.
These
are the National Science Content Standards for the STRUCTURE OF
ATOMS, that apply to Nuclear Chemistry:
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The nuclear forces that hold the
nucleus of an atom together, at nuclear distances, are usually stronger
than the electric forces that would make it fly apart. Nuclear reactions
convert a fraction of the mass of interacting particles into energy, and
they can release much greater amounts of energy than atomic interactions.
Fission is the splitting of a large nucleus into smaller pieces. Fusion
is the joining of two nuclei at extremely high temperature and pressure,
and is the process responsible for the energy of the sun and other stars.
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Radioactive isotopes are unstable
and undergo spontaneous nuclear reactions, emitting particles and/or wavelike
radiation. The decay of any one nucleus cannot be predicted, but a large
group of identical nuclei decay at a predictable rate. This predictability
can be used to estimate the age of materials that contain radioactive isotopes.
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