Activity 7: Rock Cycle
Rocks exist in three phases and change from one phase to another according to the types of mechanical and chemical stresses to which they are exposed. Using common table sugar, students will see how rocks change from one rock type to another when submitted to these different stresses.
Show students how rock properties change from rock type to rock type due to different processes.
All rocks are connected in a cycle of creation, change, and destruction called the Rock Cycle. The rock cycle begins with molten rock (magma below ground, lava above ground), which cools and hardens to form igneous rock. Exposure to weathering and erosional forces, break the original rock into smaller pieces. The smaller material (now called sediment) is carried away by rivers, wind, glaciers, and other means and is eventually deposited elsewhere. These sediments can then be buried and lithified (hardened), forming sedimentary rock.
Sedimentary rock can be deeply buried, subjected to heat and pressure, which over time, cause it to change its structure into a new rock, a metamorphic rock. Metamorphism is a big word meaning change. Eventually, these metamorphic rocks may be heated to the point where they again melt into magma.
Note that the rock cycle doesn't always have to work in this order; sometimes igneous rocks can be buried and metamorphosed, skipping the sedimentary rock phase, and sometimes sedimentary and metamorphic rocks can be uplifted and eroded to form new sedimentary rocks. It is also possible for rocks to remain unchanged in stable regions for long periods of time.
Rocks cycle through three rock types: igneous, metamorphic and sedimentary. The three rock types are connected through processes of erosion, pressure, heating and/or melting.
Ask students what is happening between each 'new' rock; heating, weathering, etc. Before each process tell students what you will do to the sugar and ask them to predict what type of rock will result.
If you have rock sugar candy you can begin the experiment with this and relate it to igneous rock.
Included National Parks and other sites:
Big Bend National Park
Utah Science Core:
2nd Grade Standard 6 Objective 1,2,3