ShareRocks & Minerals - Weathering and Erosion
Rock fragments, minerals and organic matter make up soil, but how do big rocks get so small? It happens through a process called weathering. The weathering process is a lot like the digestion process that your body does. Rocks are "chewed" up by the wind, rain, and acids into smaller and smaller pieces. Weathering is always going on and things like the rock type, temperature, and moisture levels can influence how fast it can break down. In this activity, you will model the changes that are caused by weathering and erosion.
Materials:
- Large cake pan
- Clay-type soil
- Pitcher
- Water
- Bucket
- Items to incline the pan (such as books)
- Sand
- Gravel
- Fist-sized rocks
Procedure:
- Place the clay type of soil into the large cake pan.
- Use materials such as books to incline the pan slightly at one end.
- Use the pitcher to slowly pour water over the soil starting at the top of the incline.
- Use the bucket to catch the sediments and water as they come out the bottom of the inclined pan.
- Make observations of the pan and sediments.
- Make a prediction what will happen with the next size rock.
- Proceed through each size of material as done at first.
- Place one material into the pan
- Incline the pan
- Slowly pour water starting at the top of the incline
- Catch the sediments and water in the bucket as they come out the bottom of the inclined pan.
Safety concerns: 
Be sure to follow all chemical safety rules that are specified by your teacher in all general laboratory
experiences. As with all science lab activities, the most important safety
rule is to follow all teacher directions. In this
experiment, be especially careful that water does not get onto the floor
where you might slip and fall.
Analysis:
- How does the inclined pan represent the natural structure of rock materials found on Earth?
- What process on Earth does the water movement represent?
- How does water on Earth get to the top of mountains to start the natural process of erosion on Earth?
Extension:
Obtain a rock tumbler and place different rocks into it. Observe the changes that occur to each type of rock as you go through the various steps of the tumbling process. Be careful to note which kind of rocks survive the tumbling process the best.
