Download Get the GIST on the Theories of Continental Drift and Seafloor

Get the GIST on the Theories of Continental Drift and Seafloor Spreading
Read pages 92-103 and answer the questions.
1. Who was Alfred Wegener and what was his great discovery called? _________________________
___________________________________________________________________________
2. What is the Theory of Continental Drift?____________________________________________
3. What did Wegener call his hypothesized supercontinent? ________________________________
4. What is plate tectonics? ________________________________________________________
5. Look at Figure 12 on page 94-95 and then the box beside it. What types of evidence did Wegener
find to support his Theory of Continental Drift? (You may summarize each one.)
a) _______________________________________________________________________
b) _______________________________________________________________________
c) _______________________________________________________________________
d) _______________________________________________________________________
e) _______________________________________________________________________
f) _______________________________________________________________________
6. What problem caused other scientists to reject Wegener’s theory? (page 96)
___________________________________________________________________________
7. Another scientist, Harry Hess, did mapping of the ocean floor during World War II for the U. S.
Navy. What ocean floor feature did he discover? ______________________________________
8. What was Hess’ theory called? ____________________________________________________
9. Read pages 100-101. What 2 observations did Hess make that supported his theory of seafloor
spreading? a)_________________________b)_____________________________
Now, we will act out Seafloor Spreading so that you can understand it better.
Summarize what you have learned today in exactly 20 words by writing the GIST of Continental
Drift and Seafloor Spreading and how these theories were supported.
_________________ ____________________ ___________________ _________________
_________________ ____________________ ___________________ _________________
_________________ ____________________ ___________________ _________________
_________________ ____________________ ___________________ _________________
_________________ ____________________ ___________________ _________________
Notes on Plate Boundaries and Stress Forces (pages 106-110)
10. On page 107, it explains what drives or moves the lithospheric plates. What is it?________.
11. Label the drawing of convection cells in the mantle with the words listed in the box.
a- warmer material
b- less dense
c- rises toward the crust
d- more dense
e- cooler material
f- sinks back toward the
core
12. The place where lithospheric plates meet are called plate boundaries. There are 3 types of plate boundaries shown
on pages 108-109. Write the types of boundaries, then study the illustrations at the bottom of the pages.
a) ____________________ boundaries- plates move away from each other.
b) ____________________boundaries- edges of plates bump into each other.
c) ____________________boundaries- sides of plates slide past each other.
13. What type of feature on Earth forms at divergent plate boundaries? _______________________________________
14. How are deep-ocean trenches formed? ______________________________________________________________
15. When 2 plates collide, or run into each other at a convergent plate boundary, which one subducts under the other?
_______________________________________________________________________________________________
16. What happens when an oceanic plate collides with a continental plate? ____________________________________
17. Look at Figure 22 on page 107. What feature has formed in South America because the Nazca Plate has subducted
under the South American Plate?
____________________________________________________________________________
18. What happens when 2 continental plates collide at convergent plate boundaries? ____________________________
19. Look at Figure 22 on page 107. What feature has formed as the Indo-Autralian Plate and the Eurasian Plates have
collided? _______________________________________________________________________________________
20. The third type of plate boundary is a transform plate boundary. How do scientists know if transform boundary is
present? a)______________________________-b)___________________________c)_________________________
21. Now, look at the map of Earth’s lithospheric plates on page 107. Name all 16 tectonic plates: __________________,
______________________, ______________________, _____________________, __________________________,
______________________, ______________________, _____________________, __________________________,
______________________, ______________________, _____________________, __________________________,
______________________, ______________________________, ________________________________________