CLASS SET PLEASE FOLLOW DIRECTION AND WRITE ON YOUR OWN PAPER
Snack Tectonics
Introduction:
We live on top of an immense furnace which has been burning for four and a half billion years. The outer shell of this furnace is known as the lithosphere. The Lithosphere is composed of the crust and the uppermost mantle. The lithosphere is broken into 7 large plates that slowly move around. These plates move because the sit on top of a softer layer called the Asthenosphere. As these plates move around, they are constantly interacting with each other. There are 3 basic motions during these interactions that occur along plate boundaries. Plates are either divergent, (moving away from each other) convergent, (moving towards each other) or transform (moving side to side). Today we will use graham crackers and frosting to model these different types of plate boundaries.
Part 1: Divergent Plate Boundary
a. Place 2 graham crackers on the frosting right next to each other.
b. Push down gently (Don’t break it) while pulling the two away from each other.
Picture:
Questions:
1. Are these most likely representing oceanic or continental plates?
2. What land form on the ocean floor indicates a spreading center? (label in picture)
3. In real life, whatare the 2 the major driving force of plate tectonics?
Part 2: Convergent Plate Boundaries
-Continental-Oceanic Collision
a. Dip one of your graham crackers quickly into water (1 second tops!!)
-This is because continental crust is less dense!
b. Place both graham crackers about 1 inch away from each other on the frosting.
(The wet edge of your continental crust facing the oceanic crust)
c. Gently push your dense oceanic crust down (dense!)
d. Slowly push the oceanic crust towards the continental while holding it steady until they begin to overlap.
Picture:
Questions:
4. During this event the oceanic crust is pushed under the continental crust, what is the name for this process?
5. What feature forms under the ocean at these zones? (hint: deep) (label in picture)
6. Why does the oceanic plate sink below the continental plate?
7. What also forms in an arc parallel to these boundaries? (label in picture)
-Continental-Continental Collision
a. Discard original Crackers (You may eat them if you like)
b. Take two new graham cracker squares and quickly (less than 1 sec) dip one edge of each in the water.
c. Place the graham crackers on your frosting next to each other with the wet sides facing closest to the middle.
d. Slowly push the 2 together. (You don’t need to push down because Continental Crust is not very dense and floats up high.
Picture:
Questions:
7. What features from when 2 continents crash into each other? (label in picture)
8. What is the most famous incident like this? (Tallest in the world)
9. Why doesn’t one of the plates go under the other one this time?
Part 3: Transform Boundaries
a. Pick up the 2 crackers carefully and turn them around so the 2 dry edges are next to each other.
b. Push one past the other while they are touching to simulate a transform boundary.
Picture:
Questions:
10. What 2 plates are moving this way through California right now?
11. What is the name of that boundary? (It is a fault)
12. What did we use today to represent the Asthenosphere?
13. What did we use to represent the Lithosphere?
14. Write a few sentences below briefly explaining why plate tectonics is important.