Sedimentary Rocks

 

Grade Level: Grades 4 and up
Subject: Science
Duration: 1 class period
CELs: Communication, Numeracy, Technological Literacy

Activity: Forming Sedimentary Rocks.

This activity may be done individually, in small groups or as a teacher demonstration.

Objective:

The students will understand that most sedimentary rocks are formed under the water and in lakes, seas and oceans.

Definition:

Sedimentary rocks are composed of different layers. These layers can be pebbles, sand, silt or fossil fragments.

Materials:

Jars with lids, water, some small rocks (~ 2 cm in diameter), some pebbles (~ 1 cm ), sand and soil.

Method:

1. Have the students gather rocks, pebbles, sand and soil.
2. Create a mixture of the sand, rocks, soil and pebbles and put enough of this mixture so the jar is 1/3 full. Pour in water until is nearly fills the jar. Replace the lid and shake the jar carefully.
3. Let the jar stand undisturbed. Materials will settle into layers with the coarser, heavier material on the bottom and finer, lighter materials at the top.
   

Questions & activities:

1. Have the students predict in writing what they think will happen to the materials as they settle.
2. After an appropriate amount of time have the students draw the results. Measure the thickness of the layers.
3. What happened in the jar? Why did the materials settle this way?
4. If the jars are shaken and mixed again, will the same thing happen? Try it.

Follow-up:

1. What are sedimentary rocks and how are they formed?
2. What types of sedimentary rocks might be found in Saskatchewan?