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O: You will be able to explain
rocks and the rock cycle.
Do Now: take out your pre-test.
Rocks
• Scientists define rock as a naturally
occurring solid mixture of one or more
minerals and organic matter.
• Rocks are always changing.
• The Earth recycles rocks.
Uses of rocks.
What shapes the Earth?
• Erosion
• Deposition
• Weathering
Weathering
• The process in which water, wind, ice, and
heat break down rock is called weathering.
• Weathering is important because it breaks
down rock into fragments.
Erosion
• The process by which sediment is
removed from its source is called erosion.
Water, wind, ice, and gravity can erode
and move sediments and cause them to
collect.
• Sediment is another name for small pieces
of rock, dirt, or dust.
Deposition
• The process in which sediment moved by
erosion is dropped and comes to rest is
called deposition.
• Sediment is deposited in bodies of water
and other low-lying areas. In those places,
sediment may be pressed and cemented
together by minerals dissolved in water to
form sedimentary rock.
The Rock Cycle
• Rocks are constantly changing into new
things, this process is called the rock
cycle.
Homework
• 1. Why are rocks important to us? Give at
least three reasons.
• 2. How does weathering shape the Earth’s
surface?
• 3. What is the difference between erosion
and deposition?
• 4. Why is it called the rock cycle?
O: You will be able to identify
the three main types of rocks.
Do Now: What are the three main
types of rocks? What makes them
different?
Three Main Types of Rocks
• Sedimentary
• Igneous
• Metamorphic
Sedimentary Rocks
• Formed from the
pieces or sediments
of other rocks.
• The weight and
pressure causes them
to bond together.
• You can see the little
pieces that form it and
they keep their
properties.
Igneous Rocks
• Igneous comes from
the Latin word for fire.
• Igneous rocks are
formed from cooling
magma.
• There are a couple
different types of
Igneous rocks.
Metamorphic Rocks
• Metamorphic rocks
undergo a chemical
change and turn into
a whole rock.
• They form under
intense heat and
pressure.
How are rocks classified?
The size, shape, and positions
of the grains that make up a
rock determine a rock’s texture.
Homework
• 1. What type of rock do you think that
there is the most of? Why?
• 2. Why can sedimentary rocks look very
different than other sedimentary rocks?
• 3. Why do scientists look at composition
and texture of rocks?