BACKGROUND:
The Rock Cycle explains the evolution of igneous,
sedimentary, and
metamorphic rocks that make up the Earth’s crust. Many processes, such as
volcanic activity, movement of the crust, and erosion and redeposition of
rocks on the surface, create many different environments where different
types of minerals and rocks form.
Minerals and rocks are important to our society. Many products made of
minerals and rocks are a vital part of our everyday life. For example,
concrete is a building material made of cement (calcite and clay) plus sand
and gravel. In addition, gypsum is used for sheet rock or wall board in
houses, gold for jewelry, and copper for wire.
It is difficult to distinguish minerals from rocks.
Continuously doing
exercises with the same minerals and rocks will allow students to
internalize the difference.
PROCEDURE:
- Review the differences of rocks and minerals.
- Give each group of students a bag of minerals and rocks. Instruct
students to group the specimens into the following 3 piles:
ROCKS - specimens that have the characteristics of rocks
discussed in Pre Lab
MINERALS - specimens that have the characteristics of minerals,
discussed in Pre Lab
DON'T KNOW - specimens that students cannot tell classify
- Give the students as much time as they need to examine the specimens.
Encourage them to use a microscope or a hand lens. Go around the room
and ask them if the specimens fit the characteristics of rocks or
minerals. Make sure they are aware of the difficulties in the
classification. Repeat the meaning of the characteristics many times, as
they are hard for the students to understand and remember.
- If you are using the Rock Cycle - Rocks (1A) kit, you have the
following minerals in each of the bags.
QUARTZ - (clear) fits the "crystal" definition of MINERAL.
HEMATITE - (shiny gray) fits the "pretty" definition of MINERAL.
DOLOMITE - (solid white) fits the "pure color" definition
of MINERAL.
The remaining specimens in the bag are rocks. The students do not
need to identify the rocks by name at this point. The following
rocks are included:
MUDSTONE - fine grained sedimentary rock
SANDSTONE - sand sized particles make up this sedimentary
rock
LIMESTONE - composed of shell components make up this
sedimentary rock
SLATE - flat, hard, dense compacted metamorphic rock
SCHIST - shiny, flaking metamorphic rock
GNEISS - layered metamorphic rock
BASALT - dark gray to black igneous rock
GRANITE - large grained igneous rock
RHYOLITE - light gray, fine grained igneous rock
- Encourage your students that they should classify the specimens in the
"DON'T KNOW" group into either the mineral or rock groups. If
they cannot classify some of them, leave them in the "DON’T
KNOW" pile. Sometimes even geologists cannot identify a rock
without using a microscope.
