Download 8 Grade Science Homework - O. Henry 8th Grade Science

8th Grade Science Homework
Name:
Due: October 12th, 2012
Teacher:
Date:
In this assignment we will:
8.9 (B) Relate plate tectonics to the formation of crustal features
Part1, The Theory of Plate Tectonics
Directions: Read the Passage and then answer the questions that follow using complete sentences.
Answers using incomplete sentences will receive a maximum score of ½ credit for each response.
The Theory of Plate Tectonics
In the early 1960’s geologists developed an exciting new
theory called plate tectonics. The plate tectonics theory
proposed that the Earth’s lithosphere, which is made of
the crust and uppermost part of the mantle, is not a
continuous sheet of solid rock material. The lithosphere
is divided into 12 sections called plates. The plates float
on the part of the mantle called the asthenosphere,
which has the property called plasticity. Plasticity allow
the plates to move across the top of it, carrying the
continents and ocean basins with them as they move. For
example, North American and part of the Atlantic Ocean
are on the North American Plate. Plates are thought to
move because of convection currents in the mantle.
Convection currents can cause the plates to collide, pull
apart, or slide past each other.
Figure 1: Layers of the Earth
The theory of plate tectonics provides an explanation for the way many geological events occur. New crust
forms at the spreading centers of mid-ocean ridges, while old ocean crust is being destroyed at subduction
zones. Three different types of plate boundaries, divergent, convergent, and transform boundaries, can be
identified when looking at different geological events.
1. When was the theory of plate tectonics developed?
2. The ______________________________ is divided into ___________________ sections called
plates.
3. The author defines plasticity as…
4. Plates are thought to move because…
Part 2, Plate Boundary Map
Directions: Examine the Plate Boundary Map and then answer the questions that follow. Answer your questions using
complete sentences. Incomplete sentences/responses will earn a maximum of ½ credit, per response.
1.
Shade each of the 12 sections of the Earth’s crust a different color.
2.
What to the arrows represent in the plate boundary map?
3.
Write down 5 observations about the plates and their boundaries.
4.
Write down 5 questions you have about the plates and their boundaries.
Part 3, Convection Currents
Directions: Read the paragraph about convection currents and then answer the following questions using
complete sentences. You will a maximum score of ½ credit for each incomplete answer/response.
In liquids and gases, convection is usually the most efficient way to transfer heat. Convection occurs when
substances of different temperatures mix. When a liquid or a gas is heated, it expands and becomes less
dense, so it rises. The cooler, denser liquid or gas sinks. Convection is responsible for making macaroni rise
and fall in a pot of heated water. The warmer portions of the water are less dense and therefore, they rise.
Meanwhile, the cooler portions of the water fall because they are denser. Movements like this in liquids or
gases are called convection currents.
1. Draw a convection current in the box to the right.
a. Use arrows to show the movement of matter.
b. Red will represent heated matter.
c. Blue will represent cooled matter.
Convection Current
2. Why does matter rise when it is heated?
3. Why does matter sink when it is cooled?
Energy Source/Heat
4. Complete the sentence stem below.
The relationship between plate tectonics and convection currents is that…
Part 4: Formation of Earth’s Crustal Features
Directions: Complete the table using information learned in class. Use your composition book to help you.
The Earth’s Crustal Features and How They are Formed
Illustration
Type of Boundary
Land Features or Geological
Events formed.
Real Examples…
The Andes Mountains (on the West
Coast of South America)
Convergent Boundary
(continental
crust/continental crust)
Himalayan Mountains (between India
and China/Asia)
The Alps (N. Italy, S. France, S,
Switzerland, S. Germany)
Convergent boundary
(Ocean Crust/Ocean
Crust)
earthquakes