Introduction to Rocks 7 th grade science

What are rocks?  Rocks are a combination of minerals

Are all rocks the same?  No  Not only are they different colors, but there are also different types  The three main types are igneous, sedimentary, and metamorphic rocks. Igneous: Granite Sedimentary: Sandstone Metamorphic: Gneiss

Where do rocks come from?  Rocks are created, transformed, and destroyed in a process called the rock cycle  Interactive Rock Cycle Animation Interactive Rock Cycle Animation

The rock cycle: Part 1  First of all there is no real beginning or end to the rock cycle.  However, for this lesson we will begin with igneous rocks.  Igneous rocks often forms when lava erupts from volcanoes then cools.

Igneous Rocks Can be :  Shiny  Crystalline  Porous

The rock cycle: Part 2  Secondly, the rock cycle is not a perfect circle, it does not occur in a specific sequence.  Igneous rocks can be re- melted, eroded, or pressed.  Rocks that are formed from eroded sediment are Sedimentary Rocks.

Sedimentary Rocks Can be :  Grainy, Sandy  Made of different pieces of rocks or minerals  Striped

The rock cycle: Part 3  Finally, rocks can be transformed over time to make new rocks.  Heat and pressure can create new rocks  These rocks are called Metamorphic rocks.

Metamorphic Rocks Come in a variety of styles, shapes and colors Many have stripes, but not all Many contain unique crystal and mineral formations only unique to metamorphic rocks

Review  There are review questions about rocks on the following slides.  In order to progress through the quiz in the correct order you have to click the links on the slides.  Click the “Begin Quiz” link on this page to start the quiz. Begin Quiz

1. True or False: The rock cycle always starts with igneous rocks and ends with metamorphic rocks. A. True True B. False False

2. True or False: The rock cycle does not always follow the same order. A. True True B. False False

3. Igneous rocks… A. Can be formed from pieces of sediment that have been compacted and glued together. Can be formed from pieces of sediment that have been compacted and glued together. B. Can be formed from molten magma or lava. Can be formed from molten magma or lava. C. Are formed when heat and pressure transform old rocks into new rocks. Are formed when heat and pressure transform old rocks into new rocks.

4. Sedimentary rocks… A. Can be formed from pieces of sediment that have been compacted and glued together. Can be formed from pieces of sediment that have been compacted and glued together. B. Can be formed from molten magma or lava. Can be formed from molten magma or lava. C. Are formed when heat and pressure transform old rocks into new rocks. Are formed when heat and pressure transform old rocks into new rocks.

5. Metamorphic Rocks A. Can be formed from pieces of sediment that have been compacted and glued together. Can be formed from pieces of sediment that have been compacted and glued together. B. Can be formed from molten magma or lava. Can be formed from molten magma or lava. C. Are formed when heat and pressure transform old rocks into new rocks. Are formed when heat and pressure transform old rocks into new rocks.

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