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TOPIC 2 – ROCKS AND THE ROCK CYCLE
1. Scientists have grouped rocks into three major families they are
igneous, sedimentary and metamorphic rocks. Each can be identified
by its appearance.
*Type I - Igneous rock forms when hot magma or lava cools and solidifies.
2. Magma is melted rock found below the Earth’s crust, where temperatures
and pressures are very high. Any rock heated at great depths can melt into
magma. Magma can push away or dissolve surrounding rocks.
3. When magma breaks through the Earth’s surface, in the form of a volcanic eruption,
it is called lava.
4. How is intrusive rock formed? Where is it formed? Give an Example.
How: magma cooling and hardening below Earth’s surface
Where: Below Earth’s surface (Inside)
Example: granite
5. How is extrusive rock formed? Where is it formed? Give an Example.
How: rock that forms when lava cools on Earth’s surface
Where: On Earth’s surface (Exterior)
Example: obsidian
6. What is the relationship between the size of a crystal and the length
of time it took to form?
- The faster a rock cools, the smaller its crystals will be
- The slower a rock cools, the larger its crystals will be
7. Igneous comes from the Latin word ignis meaning fire. p.361
*Type II - Sedimentary rock is made of sediment- loose material,
such as bits of rock, minerals, plant and animal remains.
These sediments become closely packed in layers and
cemented together. This arrangement of visible layers
is called stratification.
10. Define compaction.
- Process of squeezing together sediment by the weight
of water and other sediment over time.
11. Define cementation.
- Minerals dissolve as water soaks into the rock, forming a
natural cement that sticks the larger pieces of sediment together.
*Type III - Metamorphic rock means changed form.
Metamorphic rock may be formed below the
Earth’s surface when extremely high
temperature and pressure cause the original rock,
or parent rock to change form. For example shale
changes to slate which changes to schist.
Another example of Metamorphic Rock is:
Gneiss (formed from parent rock granite)
14. Draw the Rock Cycle and explain how it works. p. 368 (explain all arrows)
 All families in the Rock Cycle can become each other under the right
conditions! (heat, pressure, etc)
16. Soil can take thousands of years to form.
A soil profile is a section of the different layers that make up soil. p. 372
Topsoil is the top layer of soil, which is often rich in humus &
small rocks (fertile).
Leaching is the removal of soil material dissolved in water.
Topic 2 Review – p. 372 #1, 2, 3, 5, 6