Download BUGS Rocks Station 2 Types of Igneous, Metamorphic

BUGS
Rocks Station 2
Types of Igneous, Metamorphic & Sedimentary Rocks and
Minerals
Goal: For the children to get a sense of the variety of rocks and minerals and how they
come to have some of the characteristics that they have.
Materials:
In Backpack Kit:
• a copy of these written materials
• small chart of the rock cycle
• bag of rock samples labeled station 2
From the BUGS shelves:
• hand lenses
• box of minerals samples labeled station 2 (on the Third Grade Shelf)
Activity and Discussion: First read the materials on rocks and minerals in preparation for the
session. Each rock has a capital letter before the name. There will be an I for Igneous, an M
for Metamorphic and an S for Sedimentary. If there isn’t any capital letter before the name,
it is a mineral.
Start the session with Igneous rocks. Show the students on the rock cycle chart where the
Igneous rocks form. Ask the students what they think these rocks would look like, heavy or
light, soft or hard? Repeat this step with each category of rock.
Before passing out the rocks, explain to the students that we have limited time, that you will
be passing out one kind of rock at a time. In some cases, there will be enough of one kind
of rock for everyone to examine (with the hand lenses) that kind at the same time, but some
of the kinds of rock, they will have to share. You will pass out the next kind of rock, when
you get the first rocks back and put away. If you can do this in a sunny place, the students
will be able to see the rocks better. Be sure they don’t try to burn anything with the hand
lenses.
Igneous Rocks
Lava - is the result of magma that has been pushed up through a weakness in the
surface of the crust. Magma cools to make rock - volcanoes.
Pumice - is magma - a natural glass which contains tiny bubbles of gas.
Obsidian - is natural glass formed by the rapid freezing of magma. The freezing is
so fast that crystals don’t have time to grow.
Basalt - is a very common rock that covers thousands of square miles.
Granite - formed over a long time, so the crystals were able to grow quite large.
Rocks Station 2 Page 2
Types of Igneous, Metamorphic & Sedimentary Rocks & Minerals
Metamorphic Rocks
Serpentine - formed by the metamorphism of basalt. It is the state rock of
California.
Marble - is metamorphosed limestone.
Slate - is metamorphosed shale. It cleaves (breaks) into thin sheets. Used to
make roofs, school black boards, plus many other things.
Sedimentary Rocks
Sandstone - made of grains of sand usually held together by silica or calcite.
Limestone - made from calcite (coral, shells, bones)
Conglomerate - may be formed by a wide range of igneous, sedimentary or
metamorphic rocks - held together with a sandy material.
Fossil - may consist of the actual preserved material of the plant or animal, or of
minerals that have filled the hole left by the animal/plant after it dissolved away.
Minerals
Rocks are made of minerals. Minerals are made of elements. Elements are simple
substances that cannot be broken down into any other substance (ie. carbon, oxygen).
Most minerals are made of several elements.
Usually minerals grow into all sorts of rough shapes in the spaces between the other
minerals around them. But, if a mineral can grow freely in a hole in a rock, it may form
beautiful regular shapes with flat surfaces. These shapes are called crystals. Crystals are
the type of minerals we have in our mineral box.
Leave time for students to carefully pick out a mineral (crystal), from the box to examine
using the hand lenses. Then carefully return it to the box. They may get another crystal as
time allows. Reminder, some of the crystals are delicate.
In the backpack kit, there is a bag of rock salt (sodium chlorine NaCl). Discuss where salt is
found (salt ponds in the bay, salt mines deep in the earth) and the part salt plays in life (our
bodies need a little salt to function). They may have a few pieces of rock salt to examine
and taste. This is a mineral we eat.
NOTE: The tendency of rock is to disintegrate to sand. Please have the students be as
careful as possible to retard this process with our rock, and especially our mineral samples.
We would like them to last a long time.