Essential Science for Teachers: Earth and Space Science
Every Rock Tells A Story Children’s Ideas About Rocks
Children’s Ideas About Rocks
Below are common ideas children in grades K-6 have about this topic, compiled from research on children’s ideas about science (see the Session 1 Children’s Ideas Bibliography). Consider what evidence might refute this idea, and why a child would be likely to believe this?
1. Few children have well-developed ideas about how rocks form.
Rock can form in several ways: molten rock can cool to become igneous rock, both at and beneath the Earth’s surface; sediments weathered from rocks can settle out of water or wind to form layers that, when compacted turn into sedimentary rock; and finally, rocks that already exist can undergo changes as a result of intense pressure and high temperatures to become metamorphic rock. The processes of rock formation are not part of children’s everyday experience, and, with the exception of lava cooling to form rock, take place over immense time periods. It is challenging for children to be able to understand or visualize what is unseen.
2. Sedimentary rocks form when sediments stick together at the bottom of a river. Heat may be involved.
Most sedimentary rocks form through deposition, recrystallization, and cementation. Gravity causes sediment to settle to the bottom of a body of water. These sediments gradually accumulate, forming layers that compact the layers of sediments below. Water that surrounds the sediment contains dissolved minerals that recrystallize and cement the grains of the sediment together, forming rock. Children’s experiences are likely to be limited to sediments and sediment transport that is associated with bodies of water, like streams and ponds. It may therefore be difficult for them to comprehend the transition from sediment to sedimentary rock.
3. Rocks are unchanging.
The rock cycle is a set of processes that, over immense periods of time, convert one type of rock into another. During this process, rocks are formed and destroyed. Children perceive rock as immutable, and often believe that rocks have always been there and do not change. Also, children’s experience with the process of melting does not lead them to believe that rocks can melt.
4. Some children think that rocks are formed in a few years; others think that all rock has existed since the formation of the Earth.
With the exception of volcanic rocks, the time it takes rock to form is on the order of millions of years. Rocks of varying ages can be found today. Many children believe that dirt or sand can harden into rock, which can give rise to the idea of rock being formed in a few years. Other children may observe rock to be unchanging, which might lead them to reason that it’s permanent. Children’s ability to perceive time on a geologic scale limited—younger children’s perception of the difference between “a few years” and “since the beginning of the Earth” is fuzzy at best.
5. Rocks form where they are found.
Rocks are not necessarily formed at their current location. For example, rocks can be formed underground and then pushed or folded to a new location. Magma can travel from beneath the Earth’s surface, erupt through a volcano as lava, and travel some distance on the Earth’s surface before it hardens into rock. Smaller rock pieces that are weathered from larger rock masses can be transported over great distances by wind, water, or ice. Few children, however, have an opportunity to observe any of these phenomena.
- Driver, R., et al. “Materials and Their Properties.” Leeds National Curriculum Support Project, Part 3, Leeds City Council and the University of Leeds, U.K. (1992).
- Kusnick, J. “Growing Pebbles and Conceptual Prisms: Understanding the Source of Student Misconceptions about Rock Formations.” Journal of Geoscience Education 50, no. 1 (2002): 31-39.
- Russell, T., Bell, D., Longden, K. and McGuigan, L. Rocks, Soil, and Weather: Primary SPACE Project Research Report. Liverpool, U.K.: Liverpool University Press, 1993.
- Trend, R. “Conceptions of Geological Time Among Primary Teacher Trainees with Reference to Their Engagement With Geoscience, History, and Science.” International Journal of Science Education 22, no. 5 (2000): 53-55.
Session 1 Earth’s Solid Membrane: Soil
How does soil appear on a newly born, barren volcanic island? In this session, participants explore how soil is formed, its role in certain Earth processes, its composition and structure, and its place in the structure of the Earth.
Session 2 Every Rock Tells A Story
How can we use rocks to understand events in the Earth's past? In this session, participants explore the processes that form sedimentary rocks, learn how fossils are preserved, and are introduced to the theory of plate tectonics.
Session 3 Journey to the Earth’s Interior
How do we know what the interior of the Earth is like if we've never been there? In this session, participants examine the internal structure of the Earth and learn how it is possible for entire continents to move across its surface.
Session 4 The Engine That Drives the Earth
What drives the movement of tectonic plates? In this session, participants learn how plates interact at plate margins, how volcanoes work, and the story of Hawaii's formation.
Session 5 When Continents Collide
How is it possible that marine fossils are found on Mount Everest, the world's highest continental mountain? In this session, participants learn what happens when continents collide and how this process shapes the surface of the Earth.
Session 6 Restless Landscapes
If almost all mountains are formed the same way, why do they look so different? In this session, participants learn about the forces continually at work on the surface of the Earth that sculpt the ever-changing landscape.
Session 7 Our Nearest Neighbor: The Moon
Why is the Moon, our nearest neighbor in the solar system, so different from the Earth? In this session, participants explore the complex connections between the Earth and Moon, the origin of the Moon, and the roles played by gravity and collisions in the Earth-Moon system.
Session 8 Order out of Chaos: Our Solar System
Why do all the planets orbit the Sun in the same direction and why are the planets closest to the Sun so different from the gas giants farther out? In this session, participants gain a better understanding of the nature of the solar system by examining its formation.