Science Content Standards: 5-8
CONTENT STANDARD A:
As a result of activities in grades 5-8, all students should develop
- Abilities necessary to do scientific inquiry
- Understandings about scientific inquiry
Earth and Space Science
CONTENT STANDARD D:
As a result of their activities in grades 5-8, all students should develop an
understanding of
- Structure of the earth system
- Earth's history
- Earth in the solar system
DEVELOPING STUDENT UNDERSTANDING
A major goal of science in the middle grades is for students to develop an
understanding of earth and the solar system as a set of closely coupled
systems. The idea of systems provides a framework in which students can
investigate the four major interacting components of the earth system--geosphere
(crust, mantle, and core), hydro-sphere (water), atmosphere (air), and the
biosphere (the realm of all living things). In this holistic approach to
studying the planet, physical, chemical, and biological processes act within
and among the four components on a wide range of time scales to change
continuously earth's crust, oceans, atmosphere, and living organisms. Students
can investigate the water and rock cycles as introductory examples of
geophysical and geochemical cycles. Their study of earth's history provides
some evidence about co-evolution of the planet's main features--the
distribution of land and sea, features of the crust, the composition of the
atmosphere, global climate, and populations of living organisms in the
biosphere.
STRUCTURE OF THE EARTH SYSTEM
- The solid earth is layered with a lithosphere; hot, convecting
mantle; and dense, metallic core.
- Lithospheric plates on the scales of continents and oceans
constantly move at rates of centimeters per year in response to movements
in the mantle. Major geological events, such as earthquakes, volcanic
eruptions, and mountain building, result from these plate motions.[See Content
Standard F (grades 5-8) ]
- Land forms are the result of a combination of constructive
and destructive forces. Constructive forces include crustal deformation,
volcanic eruption, and deposition of sediment, while destructive forces
include weathering and erosion.
- Some changes in the solid earth can be described as the
"rock cycle." Old rocks at the earth's surface weather, forming
sediments that are buried, then compacted, heated, and often recrystallized
into new rock. Eventually, those new rocks may be brought to the surface
by the forces that drive plate motions, and the rock cycle continues.
- Water, which covers the majority of the earth's surface,
circulates through the crust, oceans, and atmosphere in what is known as
the "water cycle." Water evaporates from the earth's surface,
rises and cools as it moves to higher elevations, condenses as rain or
snow, and falls to the surface where it collects in lakes, oceans, soil,
and in rocks underground.
- The atmosphere is a mixture of nitrogen, oxygen, and trace
gases that include water vapor. The atmosphere has different properties at
different elevations.
- Clouds, formed by the condensation of water vapor, affect
weather and climate.
- Global patterns of atmospheric movement influence local
weather. Oceans have a major effect on climate, because water in the
oceans holds a large amount of heat.
UNDERSTANDINGS ABOUT SCIENCE AND TECHNOLOGY
- Scientific inquiry and technological design have
similarities and differences. Scientists propose explanations for
questions about the natural world, and engineers propose solutions
relating to human problems, needs, and aspirations. Technological
solutions are temporary; technologies exist within nature and so they cannot
contravene physical or biological principles; technological solutions have
side effects; and technologies cost, carry risks, and provide benefits.[See Content
Standards A, F,
& G
(grades 5-8) ]
- Many different people in different cultures have made and
continue to make contributions to science and technology.
- Science and technology are reciprocal. Science helps drive
technology, as it addresses questions that demand more sophisticated
instruments and provides principles for better instrumentation and
technique. Technology is essential to science, because it provides
instruments and techniques that enable observations of objects and
phenomena that are otherwise unobservable due to factors such as quantity,
distance, location, size, and speed. Technology also provides tools for
investigations, inquiry, and analysis.
Science as Inquiry
CONTENT STANDARD A: As a result of activities in grades
9-12, all students should develop
- Abilities necessary to do scientific inquiry
- Understandings about scientific inquiry
DEVELOPING STUDENT ABILITIES AND UNDERSTANDING
One challenge to teachers of science and to curriculum developers is making
science investigations meaningful. Investigations should derive from questions
and issues that have meaning for students. Scientific topics that have been
highlighted by current events provide one source, whereas actual science- and
technology-related problems provide another source of meaningful
investigations. Finally, teachers of science should remember that some
experiences begin with little meaning for students but develop meaning through
active involvement, continued exposure, and growing skill and understanding.
CONTENT STANDARD D: As a result of their activities in grades 9-12, all
students should develop an understanding of
- Energy in the earth system
- Geochemical cycles
- Origin and evolution of the earth system
- Origin and evolution of the universe
DEVELOPING STUDENT UNDERSTANDING
During the high school years, students continue studying the earth system
introduced in grades 5-8. At grades 9-12, students focus on matter, energy, crustal
dynamics, cycles, geochemical processes, and the expanded time scales necessary
to understand events in the earth system. Driven by sunlight and earth's
internal heat, a variety of cycles connect and continually circulate energy and
material through the components of the earth system. Together, these cycles
establish the structure of the earth system and regulate earth's climate. In
grades 9-12, students review the water cycle as a carrier of material, and
deepen their understanding of this key cycle to see that it is also an
important agent for energy transfer. Because it plays a central role in
establishing and maintaining earth's climate and the production of many mineral
and fossil fuel resources, the students' explorations are also directed toward
the carbon cycle. Students use and extend their understanding of how the
processes of radiation, convection, and conduction transfer energy through the
earth system.
ENERGY IN THE EARTH SYSTEM
- Earth systems have internal and external sources of
energy, both of which create heat. The sun is the major external source of
energy. Two primary sources of internal energy are the decay of
radioactive isotopes and the gravitational energy from the earth's original
formation.
- The outward transfer of earth's internal heat drives
convection circulation in the mantle that propels the plates comprising
earth's surface across the face of the globe. [See
content Standard B (grades 9-12) ]
- Heating of earth's surface and atmosphere by the sun
drives convection within the atmosphere and oceans, producing winds and
ocean currents.
- Global climate is determined by energy transfer from the
sun at and near the earth's surface. This energy transfer is influenced by
dynamic processes such as cloud cover and the earth's rotation, and static
conditions such as the position of mountain ranges and oceans.
GEOCHEMICAL CYCLES
- The earth is a system containing essentially a fixed
amount of each stable chemical atom or element. Each element can exist in
several different chemical reservoirs. Each element on earth moves among
reservoirs in the solid earth, oceans, atmosphere, and organisms as part
of geochemical cycles.
- Movement of matter between reservoirs is driven by the
earth's internal and external sources of energy. These movements are often
accompanied by a change in the physical and chemical properties of the
matter. Carbon, for example, occurs in carbonate rocks such as limestone,
in the atmosphere as carbon dioxide gas, in water as dissolved carbon
dioxide, and in all organisms as complex molecules that control the
chemistry of life.
CONTENT STANDARD E: As a result of activities in grades
9-12, all students should develop
- Abilities of technological design
- Understandings about science and technology
DEVELOPING STUDENT ABILITIES AND UNDERSTANDING
This standard has two equally important parts--developing students'
abilities of technological design and developing students' understanding about
science and technology. Although these are science education standards, the
relationship between science and technology is so close that any presentation
of science without developing an understanding of technology would portray an
inaccurate picture of science.