1. Bell Ringer: Please copy in your IAN! Ch.4.2 Igneous Rocks
Describe three ways that igneous rock forms.
Explain how the cooling rate of magma affects the texture of igneous rock.
Distinguish between igneous rock that cools within Earth’s crust and igneous rock that cools at Earth’s surface.

2. Igneous Rocks: Rocks of “fire”

3. Igneous rock begins as magma
Igneous rock begins as magma.  there are three ways magma can form: 1) when rock is heated, 2) when pressure is released, 3) or when rock changes composition.

4. Investigation
Today we will begin our investigation of igneous rocks by creating a visual image that relates to each of the 3 processes.
This investigation will take place in the form of a lab called, Fudgeous Rock. Lets take a look at our problem to solve, the background research, and our variables that we will be manipulating today!

5. Problem: What happens to substances during igneous rock
(fudge) formation?
Research: Refer to Chapter 4, Section 2 (pgs ) in your text to review information about igneous rocks. Continued rise in temperature can eventually melt any rock until it is molten (called magma). When the molten rock cools it forms an igneous rock. All three main types of rock (igneous, sedimentary, and metamorphic) can be melted to form magma.
Independent Variable: (I control…usually in procedure)
_______________________________________________________________________________
Dependent Variable: (what I observe…answers the lab problem)
Hypothesis: (If + IV + then + DV)
___________________________________________________________

6. 1) When magma cools enough, it solidifies to form igneous rock
1) When magma cools enough, it solidifies to form igneous rock. Magma solidifies in much the same way that water freezes.
2) Liquid magma is a complex mixture containing many melted minerals. Because these minerals have different melting points, some minerals in the magma will freeze or become solid before other minerals do.
So let’s take a closer look at our minerals/ingredients that we will turn into magma and igneous rocks…

7. Mineral Identification:
Now, let’s complete a comparison study of a few common minerals/rocks that could resemble today’s variables that we will manipulate.
Dependent Variable
(y)
Ingredient
Physical Properties
(include the phase of matter)
Earth Ingredient
(what real substance under the surface of the earth does this ingredient remind you of)
Final Observation
(what did the ingredient look like in the end)
Did it change? HOW did it change?
(YES or NO) (disappear, melt? include color & phase)
sugar
evaporated milk
butter
Marshmall-ows
chocolate morsels

8. Kaolin
Mica
Halite
Graphite
Basalt
Marble
Sulfur
Calcite

9. How do they form? When hot, liquid rock ________ cools and solidifies.
If it cools quickly, it is _____________.
If it cools slowly, it is ______________.
It takes our fudgeous rock 2 hours to cool and harden. Is that fast or slow? How would we know?

10. Origins of Igneous Rock
3 ways magma can form:
____________________________
Changes composition
It solidifies through freezing. 0 degrees Celsius vs. 1,000 degrees Celsius
Some minerals freeze faster than others. This can give igneous rocks unique textures

11. Composition and Texture
Not all igneous rocks look alike.
Cooling rate and mineral composition
Light color = ________ __________ (felsic)
Dark color= ________ (mafic rocks)
The longer it takes magma to cool, the larger the crystals
(demo)
Fine/
Above
Coarse/
Below

12. Formation: Weird Science Fact
Some igneous rocks form from cooling on the surface, but some form ___________________.
Intrusive rock –igneous rock that formed when magma hardened beneath Earth’s surface.
–Larger Crystals!
–The most abundant intrusive rock in the part of the crust makes up the continents is granite.
Granite forms the core of many mountain ranges.

14. Origin–where Extrusive are formed
–Extrusive rock–igneous rock formed from lava that erupted onto Earth’s surface.
–Smaller Crystals!
–The most common extrusive rock is basalt. Look at the rock in the tray.
Basalt forms much of the crust, including the crust beneath the ocean floor.
What about obsidian?

16. Comparing and Contrasting
•Materials -granite and basalt
•Which parts of the Earth’s crust are composed mostly of one or the other of these igneous rocks?
•Basalt -ocean floor
•Granite -continents

17. Basalt/Gravel Obsidian/Tools
Uses of Igneous Rocks
Basalt/Gravel
•Hard, dense, and durable
•Through history -tools and building materials
•Can you think of some uses?
Pumice/
Exfoliation
Obsidian/Tools
Granite/
Egyptian Statues

18. LAB Summary sugar butter
Now, let’s complete our lab data analysis and our conclusion. Let’s compare our knowledge to what we saw yesterday!
Dependent Variable
(y)
Ingredient
Physical Properties
(include the phase of matter)
Earth Ingredient
(what real substance under the surface of the earth does this ingredient remind you of)
Final Observation
(what did the ingredient look like in the end)
Did it change? HOW did it change?
(YES or NO) (disappear, melt? include color & phase)
sugar
evaporated milk
butter
Marshmall-ows
chocolate morsels

19. LAB Conclusion
Conclusion: (Complete the following sentence starters in your OWN paragraph)
The data states… 10
My data ________________ (supports/does not support) my hypothesis. 10
My conclusion is… 10 (What happens to substances during igneous rock (fudge) formation)?

20. What is its rate of cooling?
Rock Type
Where is it formed?
What is its rate of cooling?
What is the grain size?
Igneous X
Intrusive Igneous
Extrusive Igneous