The Rock Cycle: A hands on Simulation

This activity is for students to understand the rock cycle by creating a model from crayons. Students will learn the three types of rocks formed through the rock cycle. Sedimentary rocks. Metamorphic rocks and Igneous rocks. Students will identify some rocks at each part of the cycle.

This is a lab that a class of fourth grade students of 30 can conduct. The will need to have some understanding of the rock cycle and the vocabulary used when talking about rocks and the rock cycle. The activity needs about an hour and needs to be near a heat source.

This lesson is intended to support prior teaching of the rock cycle. Therefore, the intended time is two 45 min teaching period. The first being the background and vocabulary and the second being the activity. After describing the cycle using the attached vocabulary sheets and drawing it into a science notebook, the second lesson will give a hands-on learning of the rock cycle. A description of the activity and the vocabulary sheets can be found at https://www.mjksciteachingideas.com/rocks.html.

To gain an idea of how the rock cycle works, the world rock tour that began in Hawaii might end in east Greenland. Millions of years ago there, magma deep inside the Earth forced its way into another rock and solidified. This created an igneous rock. Then, intense pressure in the Earth caused the rock to up-heave, fold, and crumple, until it became an entirely new rock: a metamorphic rock. That new rock now makes up a mountain formation in Greenland.
And the rock cycle continues today. Everyday, little pieces of the mountain rock are worn away by water and wind. Those pieces collect somewhere and are compressed into new sedimentary rocks, which will continue to change and reenter the cycle as different metamorphic rocks or as melted material that can form new igneous rock. Then the process will begin all over again. 

Igneous rocks are created when molten material such as magma (within the Earth) or lava (on the surface) cools and hardens. The hot material crystallizes into different minerals. The properties and sizes of the various crystals depend on the magma's composition and its rate of cooling. Examples of Igneous rocks: Granite, Obsidian, Basalt, Pumice, Andesite, Diorite, and Rhyolite

Sedimentary rocks are made up of sediments eroded from igneous, metamorphic, other sedimentary rocks, and even the remains of dead plants and animals. These materials are deposited in layers, or strata, and then are squeezed and compressed into rock. Most fossils are found in sedimentary rocks. Examples of Sedimentary rocks: Sandstone, Shale, Conglomerate, Limestone, Chert, Coal, and Gypsum

Metamorphic rocks are produced when sedimentary or igneous rocks are transformed by heat and/or pressure. The word "metamorphic" comes from the Greek language, which means "to change form." Examples of Metamorphic rocks: Marble, Slate, Quartzite, Schist, and Gneiss


Activity:
Have students use wax crayons, which will be taken apart and put back together for a simulation of the entire rock cycle. 
The whole crayon represents an Igneous rock. To show Weathering: shave the crayons. Then Erosion occurs so pick up the crayon shavings and move them. The shavings (rock pieces) stop moving in various places this is called Deposition. One place rock pieces can be deposited is underground where compaction occurs. To show this put the crayon shavings onto some aluminum foil and fold into a packet. 
Compaction forms Sedimentary Rocks: put packet between your hands and apply light pressure. Add heat and pressure to form Metamorphic Rocks: put packet between your hands and apply heavy pressure. 
Melting and cooling brings us back to the form of an Igneous Rocks: melt the compressed crayon shavings. You can do this by placing the foil packet on an electric griddle. You can then pour the melted crayon over ice cubes to form "pumice," or into ice water to form "obsidian," or over warm or hot water to form an Igneous rocks, such as "diorite" and granite." 


I would then have students go back to the rock cycle diagram in their notebooks and add any new learning. I would have them use their vocabulary sheets and glue them into their notebook matching the correct definition to each word.
vocabulary sheet for the rock cycle (Acrobat (PDF) 7kB Aug3 09)

As a safety guideline with the heating of the packets and then pouring them into the different cups - I let the students choose their outcome for their rock cycle and then I do the pouring for them. It is helpful to have extra hands in the room for this reason.

This activity has only been done in a small group and the assessment was done through a question/answer as we moved through the activity. In a larger group situation, I would use the science notebook and vocabulary sheets to assess the students learning of the rock cycle.

4.2.1.2.2 - Matter changes as it is heated and cooled
4.3.1.3.1 - Earth structure and its formation