Earth & Space Science Lesson 8: Sedimentary Rocks & Erosion

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Read:

Geology Rocks! pg. 22-27, 68-69

Everything Rocks & Minerals, pg. 26-27

    

Watch:

What is Erosion? (Caution: Refers to "Mother Nature" instead of God's hand in creation...)

Explore: 

This is the explanation of erosion from pg. 44-45 of  Explore Rocks & Minerals! (Brown, Cynthia & Nick)

Sand is a central ingredient in the second rock form, sedimentary rocks. These are rocks made from sediments, or tiny particles that are pressed tightly together into stone. To understand how most sedimentary rocks are formed, you must understand how the sand got to the beach in the first place. It happens through a process called erosion.

Imagine your'e a huge boulder high on a mountain. For the first few thousand years or so, you think you're indestructible. But slowly, rain and wind and ice work on you. One winter, you crack a little bit. Water drips into these cracks and freezes, and the crack gets bigger. Maybe wind knocks a rock against you, breaking off a piece. Before you know it-- after many more thousands of years, that is-- you're nothing more than a load of smaller rocks tumbling down the mountainside.

During a rainstorm, you're swept into a stream. In the stream you're broken down into smaller rocks, and your sharp edges are smoothed. These small pieces of rock are called sediments, like pebbles, sand, and mud. You might settle at the bottom of a river, or be carried out to the ocean, or be blown by the air to become part of a sand dune. But one thing is for sure: you've been eroded!

Activity 1: Wash & Wear

Complete the "Wash & Wear" activity on pg. 68 of Geology Rocks! to demonstrate the process of erosion.

Activity 2: Rocks in a Jar

Complete the "Settle Down" experiment on pg. 24 of the Geology Rocks! book.

As an alternative, you could do this one:

Make a Rock in a Cup

Activity 3: Sand Sculptor!

Complete the "Be a Sand Sculptor!" Activity on pg. 25 of the Geology Rocks! book.

OR

Better understand the experience of how sand transforms into sedimentary rock with the experiment on Page 15 of this document.