Weathering, erosion and deposition
1 min 34 s. The words are spoken and shown in the picture; the player can also show them as subtitles.
For the Earth and Space Sciences Regents. Topic: Weathering, erosion and deposition, with the past questions on it.
What Dr. Mars says (the words of the video)
How does a river sort rock pieces by size?
Physical weathering breaks rock into pieces.
Chemical weathering changes the minerals.
Erosion carries the pieces away, mostly by running water.
Dr. Mars breaks off a piece with his hammer.
The steep stream flows fast.
Fast water can carry big pieces.
In the lake, the water slows down.
Slower water can carry only smaller pieces.
The biggest pieces settle first.
Tiny clay settles last, farthest from the shore.
This is called horizontal sorting.
Boulders, pebbles, sand, silt, then clay.
Dr. Mars shakes the sediment through a sieve.
The largest pieces stay on top. The smallest fall to the bottom.
Check yourself! Which spot collects the smallest pieces: A, B, or C?
Think about which pieces settle last.
Answer: C! The smallest pieces settle last, farthest from the shore.
Clay is the smallest: it passed through every sieve.
Dr. Mars. Free practice for the New York Earth and Space Sciences Regents.