Smooth River Rock and Compilation

Small rocks have been rounded as they were carried downstream by the energy of the water and that the jagged edges are worn off from tumbling along the bottom of the stream. They were deposited in a low area within the stream and the rocks pile up in that place.

Why are the rocks smooth without jagged edges?

•  
• Why is there a pile of rocks all in one place in the stream?

Students could:

• Look at smooth river rocks and jagged rocks from a quarry in the classroom and determine which location they came from.

• Sciencing | How are River Rocks Formed?: Photos and description of weathering of rocks in rivers.
• PBS LearningMedia | 60-Second Science: Weathering Rocks: This video demonstrates why some rocks are smooth and round using plastic jars, rocks, water and a sieve.