Students will learn that glaciers are major forces in changing the landscape and were major contributors to the scene we see today. Students will identify terminal and lateral moraines, the headwall, cirques, tributary glaciers, and hanging valleys.
Grades: 4 – 6
Time: two 1-hour sessions
Subjects: Earth science, economics
Materials:
- A small sandbox
- A supply of sand, gravel and assorted small rocks
- A variety of sizes of elongated plastic containers
- Access to a freezer
Procedure:
1. Freeze gravel and small rocks into ice blocks so they will have a rough bottom when they start to melt.
2. Keep the sand, gravel, and rocks in the sandbox damp enough to mold into mountains.
3. Have the students form mountains and river valleys in the sand.
4. Produce a large ice block to represent a large mountain glacier and several smaller blocks to represent smaller tributary glaciers. 5. Place the large block at the head of the valley and slowly bulldoze a path down the river valley. Point out the gouging and plucking along the way. When you reach the terminal point of the valley, point out the terminal moraine. Be sure that you are gouging nearly to the bottom of the sandbox or trough. Point out the lateral moraines along the glacier’s path.
6. Give some of the students small glaciers and invite them to work a few tributary glaciers. Ask if they can produce hanging valleys, cirques, etc. . . . When they have finished have them leave their remnant glaciers against the headwalls.
7. Some time later have the students look at the debris left in the cirque as the ice block melts. Ultimately there will only remain a little pile of till and a small tarn.
Do the deposits of glaciers determine where farms are located? Are loggers affected by glacier deposits? How?
Variations and Extensions:
Take a field trip to Glacier! Do some glacial visualization with the large relief maps in the Waterton, Apgar and St. Mary Visitor Centers when you visit the park.
Assessment:
As a special treat and review, get several half gallon blocks of Neapolitan ice cream, marshmallow cream topping, ground nuts to represent rocks, and whatever else you might find tasty and relevant. Put the ice cream blocks together, then get down to business with an ice cream scoop. While reviewing glacial terminology and carving formations with the scoop, fill cups for the students who can correctly identify the latest formation. Of course early winners need to give others their chance once they have been served.
