The Physical Setting
The following synopses based on Benchmarks for Science Literacy,
outlines curricular milestones for teaching about the earth's physical setting.
The accompanying instructional activities, Mud Slide,
and Stream Works, provide practical examples for
translating the Benchmarks recommendations to the classroom. In these
activities we take a close look at the teacher as facilitator - a basic
concept in the reformed classroom.
The Physical Setting: Teaching in the Middle School and Secondary
Grades
The Physical Setting: Teaching in the Early
Grades
It's all connected: the earth, the stars, the weather, the elements. All
the pieces of nature work together to form our physical surroundings. Teaching
young children about that interconnectedness stretches their imagination
and understanding. The child's knowledge of nature's relationships will
develop over many years. Ideas will be visited again and again in new contexts
and with greater detail. Such concepts as energy transfer, gravitation,
photosynthesis, and the water cycle will build slowly as children mature
and learn in different contexts.
In the early years the curriculum should focus on experiences and
ideas that are accessible to children - for example, how planets differ
from the earth or the variety of materials found in nature. The curriculum
should build on the first steps to understanding, using what children can
observe - the movement of the sun and moon, the patterns of seasonal change
and changes in the earth's crust that are evident to anyone who looks for
them.
Young children are especially curious about how the world works. In the
early grades, young students can start with the ways organisms, themselves
included, modify their surroundings. Encourage young children (grades
K - 2) to look at what things change and what causes change around them.
For example, as people have used the earth's resources, they have altered
some earth systems. By the end of 2nd grade, students should realize
that some events in nature have repeating patterns. They should be aware
that chunks of rocks come in many sizes and shapes from boulders to grains
of sand and even smaller.
As students progress (grades 3 - 5), they will accumulate more information
about the physical environment, becoming familiar with the details of geological
features, observing and mapping locations of hills, valleys, and rivers.
Students should learn what causes earthquakes, volcanos and floods and how
these forces shape the earth's surface. Since children may show more interest
in the phenomenon itself than the role it plays in sculpting the earth,
teachers should start with immediate interests and work toward the science.
Students at this stage should observe elementary processes of the rock cycle:
erosion, transport, deposition. Water and sand boxes and rock tumblers can
provide firsthand examples. They should learn to use magnifiers to inspect
rocks and soils. They can build devices that demonstrate how wind and water
shape the land and how forces can make wrinkles, folds, and faults in the
earth's crust. Remember: elaborate classification is not necessary. The
point is not to classify rigorously, but to notice the different pieces
of the big picture and to examine the processes involved.
This synthesis is based on several portions of "Processes that Shape
the Earth," a chapter in Benchmarks for Science Literacy by the American
Association for the Advancement of Science (AAAS).
Activity: Mudslide
The Teacher as Facilitator
The Physical Setting: Teaching in the Middle
School and Secondary Grades
By the middle grades students should be able to understand most of the main
features of the physical and biological factors that shape the face of the
earth.It is especially important that they understand how sedimentary rocks
formed periodically, embedding plant and animal remains and leaving a record
of the sequence in which the plants and animals appeared and disappeared.
Besides the relative age of the rock layers, the absolute age of those remains
is central to the argument that there has been enough time for evolution
of species. While the process of sedimentation is understandable and observable,
students may find it difficult to imagine the span of geologic time.
In the study of processes that shape the earth, students by the end of the
8th grade should know that the interior of the earth is hot and that
heat flow and movement of material within the earth cause earthquakes to
occur and volcanoes to erupt. Changes on the earth's surface can be abrupt
(earthquakes) or slow (glacial cutting) and the earth's surface is shaped
in part by the motion of water and wind over very long periods of time.
From the 9th through 12th grades study should turn to modern explanations
for the phenomena the students have learned descriptively and to consideration
of the effects that human activities have on the earth's surface. Reduction
of the forest cover, increases in the amount and variety of chemicals released
into the atmosphere, and intensive farming have changed the earth's land,
oceans, and air. Some of these changes have decreased the capacity of the
environment to support some life forms.
Questions of environmental policy should be pursued when students become
interested in them, usually in the middle grades, or later. Care
should be taken not to bypass science for advocacy. Critical thinking based
on scientific concepts and understanding is the primary goal for science
education.
Students should see as many varieties of landforms and soils as possible.
Knowledge of radioactivity, which should occur in the high school years,
helps students understand how rocks can be dated and helps them appreciate
the scale of geologic time.
By the end of the 12th grade students should know that the formation,
weathering, sedimentation, and reformation of rocks constitute a continuing
"rock cycle" in which the total amount of material stays the same
as its forms change. The concept of plate tectonics is formally introduced
at the high school level and by the end of high school students should know
that the solid crust of the earth consists of separate plates that ride
on a hot, denser layer. The crust sections move very slowly, pressing against
one another in some places, pulling apart in others. The surface layers
of the plates may fold, forming mountain ranges.
This synthesis is based on several portions of "Processes that Shape
the Earth," a chapter in Benchmarks for Science Literacy by the American
Association for the Advancement of Science (AAAS).
Activity: Stream Works
The Teacher as Facilitator
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