Lesson 3 Task 2 Answers
Question 1: Small rocks or pebbles which are too big to be carried within the water are transported and bounce along the bottom of the river bed.
Question 2: When pebbles grind along the river bank and bed in a sand-papering effect.
Question 3: This occurs when rocks are porous (contain holes) or permeable (allow water to pass through). Water enters cracks in the rock. When temperatures drop, the water freezes and expands causing the crack to widen. The ice melts and water makes its way deeper into the cracks.
Question 4: Biological = Rocks are broken down by living organisms.
Mechanical = Breakdown of rocks into smaller rocks by water, ice or wind.
Chemical = The disintegration of rocks caused by reactions.
Question 2: When pebbles grind along the river bank and bed in a sand-papering effect.
Question 3: This occurs when rocks are porous (contain holes) or permeable (allow water to pass through). Water enters cracks in the rock. When temperatures drop, the water freezes and expands causing the crack to widen. The ice melts and water makes its way deeper into the cracks.
Question 4: Biological = Rocks are broken down by living organisms.
Mechanical = Breakdown of rocks into smaller rocks by water, ice or wind.
Chemical = The disintegration of rocks caused by reactions.