BACKGROUND:
The Rock Cycle is a very important concept for children to understand. It
is a model which explains how one type of rock can become another type of
rock if the environment where the rock "lives" changes. For
example, rocks at the Earth’s surface can be pulled into the crust, where
they experience high pressures and temperature conditions. This
environmental change may cause the rocks to melt, eventually forming a new
rock.
In the first grade, it is difficult for the students to understand all
the processes of the Rock Cycle, but an explanation of the environments
where rocks can form will help students to understand how rocks are
"recycled."
Minerals make up rocks. Rocks and minerals are related but they have
different characteristics. A person, for example, has organs like a liver or
a stomach, but when the parts are put together they form a person. A liver
by itself does not provide any information about the kind of a person it
came from, and although we know there is a heart inside each person, we
cannot see it from the outside. The same problem arises with rocks. We know
that minerals make up the rocks, but we cannot always see them.
Rocks are usually ugly to the eyes of a child. They are usually gray or
brown, unless they live in areas where rocks are spectacular like the Sierra
Nevada exposures of granites , the sandstones of Colorado and Utah, or the
basalt flows in Hawaii.
PROCEDURE:
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The connection between minerals and rocks can be illustrated by
getting several balls of different color clay. A red ball of clay is a
"pure" red mineral. A blue ball of clay is a "pure"
blue mineral. A yellow ball of clay is a "pure" yellow
mineral. Take a piece of the blue, red, or yellow and make another ball.
This mixed mineral ball would represent a rock. If you keep mixing the
"rock" all the colors of the clay will mix and you will get a
grayish brown color. You know the red, blue, and yellow are there, but
you just can’t see them. Minerals make up rocks.
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Review the characteristics of rocks and minerals, using the chart
below. As you review each characteristic, explain its meaning carefully.
Be aware that these distinctions are generalizations. Many exceptions
occur, due to the wide variety of mineral and rock compositions. The
students will find identification becomes easier with practice.
