Riverstone Investigation Concepts

CJ Thompson introduces riverstones and explains their formation in rivers. The video guides viewers through an experiment to observe how rocks change over time in water. Required materials include small rocks, a jar, a scale, and a data table. The experiment involves shaking water-soaked rocks in a jar and measuring their mass at intervals. The video concludes with questions about the observed mass loss and the cloudy water, encouraging further thought.

What is the primary factor that shapes riverstones over time?

• Wind erosion

• Chemical reactions

• River water movement

• Animal activity

Which materials are recommended for the riverstone investigation?

• Slate and shale

• Granite and marble

• Sandstone and limestone

• Basalt and pumice

What is the purpose of soaking the rocks before starting the investigation?

• To make them heavier

• To change their color

• To clean them

• To allow them to absorb water

What is the initial mass of the rocks recorded in the investigation?

• 70 grams

• 60 grams

• 50 grams

• 40 grams

How often are the rocks shaken during the investigation?

• Every 2 minutes

• Every 3 minutes

• Every 5 minutes

• Every 10 minutes

What should be recorded if there is no change in the mass of the rocks?

• Zero for the difference

• A negative value

• The previous mass

• A positive value

What is the total mass loss of the rocks by the end of the investigation?

• 12 grams

• 10 grams

• 8 grams

• 5 grams

What does the cloudy water in the jar indicate?

• Tiny particles from the rocks

• Chemical reaction with the jar

• Evaporation of water

• Presence of dissolved minerals

What might the residue at the bottom of the jar represent?

• Particles too large for the strainer

• Chemical deposits

• Dirt from the rocks

• Particles too small for the strainer

What question is posed about the mass of the residue?

• What is its color?

• Is it heavier than the rocks?

• Does it dissolve in water?

• How much does it weigh?