Objective: To simulate the rock cycle using crayons.
Materials: Crayons, 1 coin, Aluminium foil squares, paper towels
Part 1: Making Sedimentary Rocks
A) Erosion
1. Rocks are broken down by the forces of nature. In this simulation the crayons
represent the rocks, the coin represents erosion (wind, sun, ice, rain) that cause
rocks to break down into smaller pieces.
2. Erode your rock. Use a coin to shave your crayons into small pieces. Collect
your shavings on a paper towel. Be as neat as you can.
3. Answer the following questions about your eroded rocks:
a) What do the different coloured crayons represent?
b) Are the fragments all the same shape or size? Describe.
c) Would this be true of rock fragments in nature?
d) What are some of nature’s tools to erode rocks?
B) Deposition
1. Once rock fragments have been created, they are usually moved by some force
of nature like gravity and dropped in a new location (Deposition). Next you will
act as a depositional force.
2. Have each lab partner pile their “rock fragments” in a neat pile in the center of
the aluminium foil square. This equivalent of moving and laying down
(Depositing) of rock fragments.
3. Answer the following questions about deposition:
a) Describe the shape and size of spaces between your “rock” pieces. Are they
large or small? Regular or irregular shaped?
b) How does nature move and lay down rock?
C) Compaction/Cementation
1. This part requires you to understand the cementation process. Spaces between
the fragments are reduced in size by pressure (Compaction) and filled in with
cementing agents (Cementation). The compaction process occurs as sediment
layers are continually covered by new layers of sediment. The lower layers
become compacted by the weight of the new layers above.
2. Carefully fold the loose layers of crayon shavings inside the aluminium foil.
3. Bring your folded packet to the front of the classroom for Mrs. McPherson to
compact your eroded rocks.
4. Answer the following questions about compaction:
a) Do you see any layers? Are they thick or thin?
b) Describe the compaction: Are they tightly or loosely compacted?
Save one piece of sedimentary rock.
Part 2: Making Metamorphic Rock
A) Heat and Pressure
1. Pressure and temperature increase as you go deep into the Earth. Metamorphic
rock may become contorted in appearance and actually flow like a plastic
material, in response to the HEAT and PRESSURE to your sedimentary rock.
2. Rewrap the loosely compacted, sedimentary rock-type crayons in the aluminium
foil, in the shape of a small bowl.
3. Bring your aluminium foil to the front of the classroom for Mrs. McPherson to
apply heat and pressure to your sedimentary rock.
4. Answer the following questions about heat and pressure:
a) Do you see any layers? Are they thick or thin?
b) Describe the compaction. Are they tightly or loosely compacted?
Save one piece of Metamorphic rock.
Part 3: Making Igneous Rock
A) Melting and Cooling of Rock
1. Igneous rocks from deep within the Earth. They originate in magma chambers
embedded in solid rock.
2. Take your remaining pieces of “sedimentary” and “metamorphic” rocks and place
them into a piece of aluminium foil. Fold the foil into a bowl shape. Take it to
Mrs. McPherson to demonstrate the melting and cooling process that forms
igneous rock.
3. Answer the following questions about igneous rocks:
a) Describe what the melted “rock” looked like.
b) Describe the cooling process and the final appearance of the igneous rock.