Download Chapter 15 Sections 1 and 2 Guided Reading Questions

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Chapter 15 Sections 1 and 2 Guided Reading Questions
15.1
1. How are rocks and minerals alike? They are both naturally formed solids.
2. How are rocks and minerals different? Minerals have a definite chemical composition, rocks
don’t.
3. Name two rocks that contain NO minerals. Obsidian and Coal
4. Name 4 different purposes that rocks can be used for. Building, art, pavements, and a source
for metals.
5. How are rocks used to study changes through time? Rocks contain artifacts from the past, show
weather patterns, and record events such as earthquakes and volcanoes
6. Explain the rock cycle. Natural and continuous cycle of rock formation, destruction, and reformation
7. What are the three different rock types? Igneous, sedimentary, metamorphic
8. What is the most common rock at the Earth’s surface? What is the percentage? Sedimentary,
75%
9. What percentage of the entire crust is made up of sedimentary rock? 5%
10. Why are sedimentary rocks most common at the surface but not deeper in the crust?
Sediments are primarily created from the process of weathering and erosion which happen at
the surface.
15.2
11. What type of rock forms when molten rock cools? Igneous rocks
12. What are the two different types of molten rock and what makes them different? lava- is at or
above the surface (exposed to air) and magma is beneath the surface and not exposed
13. How are igneous rocks classified? mineral composition and crystal size
14. What type of rock is formed from magma? and, give an example intrusive, granite
15. What type of rock is formed from lava? and, give an example extrusive, obsidian
16. What determines the texture of an igneous rock? rate of cooling
17. What are the three factors that help form large crystals in INTRUSIVE igneous rocks?
1. The interior of the Earth has a high temperature
2. When magma cools it cools very slowly inside the Earth.
3. The cool slowing allows time for mineral crystals to form.
18. How do the high temperatures within Earth affect the cooling rate of magma? slows the
cooling
19. What are the three factors that inhibit crystal growth in EXTRUSIVE igneous rocks?
1. Exposure to air lowers the temperature.
2. The lower temperature cools the lava quickly.
3. The quick cooling keeps crystals from forming.
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20. How does an igneous rock with both large and small crystals form? The magma started cooling
and then an eruption occurred and before it was completely cooled it was exposed and cooled
quickly.
21. What is Ship Rock and how was it formed? a land formation formed from a cooled magma
chamber millions of years ago.
22. Is Ship Rock and intrusive or extrusive rock formation? intrusive, exposed by weathering and
erosion
23. How are formations of intrusive igneous rocks different from other types of rock? they are
more durable, longer-lasting
24. If granite within the Earth melts, then erupts at the surface, what type of EXTRUSIVE rock is
likely to form? rhyolite or pumice
25. What mineral group is used to classify igneous rocks? silicates
26. What elements are found in silicate compounds? silicon and oxygen
27. How does the amount of silica in an igneous rock affect the color of the rock? high silica- light
in color, low silica- dark in color
28. What is the difference in between lava flow in lava that has a lot of silica and lava that doesn’t
have a lot of silica? lots of silica- thick, slow low silica- thin, fast
29. What kind of volcano forms from lava with a lot of silica, and what kind of eruptions do they
make? steep-sided cone shaped volcano, explosive eruptions