Download Objective: Demonstrate how three different types of rocks are formed

Name: ______________________________
Let’s Rock - A Simulation of the Rock Cycle
Objective: Demonstrate the formation of the three main types of rocks
Time Required: Two single periods
Materials:
Per Group:
Aluminum Foil (1 sheet approximately 12” x 24” and additional foil to make molds)
3 sheets of plain printer paper
15 crayons (5 light colored, 5 intermediate and 5 dark colored if possible)
“Hammer” (a mallet or anything else that can be used to crush crayons)
Numerous sheets of newspaper
Hot Hand Protectors
Per Class:
1 Hot Plate
2 pieces of Wood (cabinet shelves work well)
Safety:
 Use Hot Hand Protectors to handle the hot packages (not your bare hands)
 Use caution when hammering and handling hot materials.
Procedure:
1. Each group should select 15 crayons. Crayons should include 5 light colored crayons, 5 intermediate
colored crayons, and 5 dark colored crayons.
2. Strip the paper from the outside of the crayons (very important)
3. Separate the crayons into 3 groups according to their color: 5 light-colored, 5 medium-colored and 5 darkcolored crayons, placing each group on a separate piece of plain printer paper.
4. From this point the procedures will refer to the crayons as rocks.
5. Wrap each set of rocks (crayons) with the plain paper, folding the ends over like you are wrapping a gift
and then wrap the package with newspaper. You should now have three 3 packages.
6. BREAK UP THE ROCKS by hitting each package with a “hammer”. The rocks need to be broken into
small pieces called SEDIMENT. Do not mix the different color rock sediment. The ideal sediment size is
2mm or less.
Note: Hitting the packages extremely hard will not give you a good result because the paper will stick to the
crayons. Repeated lighter “hits” works best.
7. Get a piece of aluminum foil and fold it in half to create a double-sheet of foil.
8. Open your paper/newspaper packages and pour one color LAYER of SEDIMENT onto the aluminum foil.
Spread it out to form a flat layer approximately 6cm x 6cm. Pour another color layer of sediment on top of
the previous layer. Repeat this step until all of your sediment is gone. (It should look like a multicolored deck
of cards.)
9. Fold the aluminum foil over the top of the layers of sediment without disturbing the layers. The foil should
completely wrap around all layers of sediment. (Wrap it like a birthday gift). You should now have ONE
package.
10. Now place the foil/rock package between two pieces of wood on the floor. Apply PRESSURE to the
foil/rock package by standing on the wood (be careful). After applying the pressure open up the foil/rock
package and observe the newly formed rock. Unfold and observe.
GO BACK TO YOUR SEAT
Answer the following questions
a. What type of rock is formed from sediment (igneous, sedimentary, or metamorphic)?
______________________________
b. State the two processes which form sedimentary rock (the two steps in lithification).
(1) ____________________ - extreme pressure pushes the fragments together and squeezes out air
and water from between the fragments.
(2) _____________________ - water carries dissolved minerals through sediment, the minerals left
behind form the cement to hold the rock fragments together.
c. Rocks formed from sediment are classified according to the kinds of sediment that form them. State the
classes of sedimentary rocks.
(1) ____________________ - formed from rock fragments carried away from their source by water,
wind, or ice left as deposits. Classified base on the size of the fragment.
(a) Gravel/Coarse - gravel sized fragments or pebbles.
(b) Sand/Medium - sand-sized fragments
(c) Clay/Fine - clay sized fragments
(2) ____________________ - formed from minerals that have been dissolved in water.
(a) An example of a precipitate is ___________________________
(b) Examples of evaporates are calcite, halite, and gypsum
(3) ____________________- formed from the remains of decaying organisms.
Coal is an example of sedimentary rocks formed from decaying organisms.
RETURN TO THE LAB
11. Fold up the aluminum foil (re-wrap the package) and check that there are no holes or tears in the foil. If
you find holes, re-wrap the package in a new piece of aluminum foil. Place the foil/rock package on the tray
in the toaster oven (under the fume hood). Add HEAT to the foil/rock package for about 1-3 minutes.
(The goal is to heat the rock but not to melt the rock.)
12. Remove from oven. (Be careful the foil may be hot!!) Immediately place the foil/rock package between
two pieces of wood. Stand on the wood again to apply PRESSURE to the foil/rock package.
GO BACK TO YOUR SEAT
13. Unfold and observe how the newly formed rock differs from the previous rock. Record observations below:
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14. Answer the following questions
a. What types of rock are formed when heat and pressure are applied to the rock (steps 12 - 13)?
____________________
b. Name two types of metamorphism that occur in the crust of the earth.
(1) ____________________ - when rocks come into direct contact with magma. Occurs when hot
magma pushes through existing rock.
(2) ____________________ - heat and pressure created by tectonic activity. Occurs over large areas
of rock during mountain building events.
c. Rocks formed from heat and pressure, are classified according to their structure.
(1) ____________________ - rocks with visible layers, or bands.
(a) Examples of rocks formed from heat and pressure with visible layers or bands include Slate,
Schist, and Gneiss.
(2) ____________________ - rocks without visible layers or bands.
(a) Examples of rocks formed from heat and pressure without visible layers or bands include
quartzite and marble.
RETURN TO THE LAB
15. Keep the foil unwrapped – fold the edges over to create a mold. Make sure there are no holes in the
aluminum foil (get new foil if you need to). Choose any shape you want – it is ok to break your rock up to
make it fit in your mold.
16. Place the mold back in the toaster oven until the rock MELTS. Melted rock is called MAGMA when the
liquid rock is underground and lava when it is on the earth’s surface.
17. Once the rock has melted carefully pull it out and let it COOL. Caution: hot magma will burn, be careful!
Observe how the newly formed rock looks different from the previous rock.
GO BACK TO YOUR SEAT
18. Answer the following questions
a. What types of rock are formed when molten rock cools and hardens (steps 17 - 18)?
________________________________
b. Rocks that form from cooling and solidification of magma are classified according to where the molten
rock cools and hardens.
(1) ____________________ Igneous rocks form deep below the crust.
(2) ___________________ Igneous rocks from onto the earth’s surface from the rapid cooling of
lava.
c. The texture of igneous rocks is largely determined by the cooling rate of the magma that formed the rock.
(1) Intrusive igneous rocks form from magma that cools and hardens slowly deep underground, the
slow loss of heat allows time for the minerals in the cooling magma to form large crystalline
grams to produce rocks with a ____________________- grain texture.
(2) Extrusive igneous rocks form when lava cools rapidly on the earth’s surface, the rapid loss of
heat does not allow for time for large crystalline grains to form and produce a rock with a
____________________ - grain texture.
(3) Initially forming from magma that cools slowly and then more rapidly as it comes to the surface
produces a rock with large grains embedded within a mass of small grains is called porphyritic.
d. The mineral composition of an igneous rock is determined by the chemical composition of the magma
from which the rock develops.
(1) Felsic rocks form from felsic magmas that are ____________________ colored and high in
____________________.
(2) Mafic rocks form from mafic magmas that are ____________________ colored and high in
____________________ and ____________________.
CLEAN UP YOUR AREA, PUT MATERIALS BACK, AND RETURN TO YOUR SEAT.
The Rock Cycle:
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Fill in the rock cycle below. Include connecting terms on the arrows where appropriate.
Use bold, all CAP terms from the procedures as the word bank to complete the concept map.
Fill in the bold boxes first and then fill in the other boxes.
Type of rock from question #19a:
Type of rock from question #15a:
_______________________________
_______________________________
Type of rock from question #11a:
______________________________
Analysis and Critical Thinking
1. Based on the lab, how would you classify the type of igneous rock you formed?
__________________________________________________
2. Based on the lab, a sedimentary rock became a metamorphic rock and then became an igneous rock. In the
“real world” do all rocks go through all three stages? Support your answer.
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3. Based on this lab activity, define the rock cycle (in your own words).
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4. Of the three types of rocks you investigated, which one would mostly likely contain identifiable fossils?
Support your answer.
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5. Which specific processes in the rock cycle occur beneath the Earth’s surface? Support your answer.
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