Download Basalt and Granite Density and Subduction Lab

Subduction and Density Lab
Purpose: To test the density of the rock that makes up the ocean crust and
the continental crust. The denser crust moves beneath and melts at the
subduction zone.
I.
Problem: How does density play a role in subduction?
II.
Background Information: 3 sources are required: From
Anderson’s class notes on __________. A plate boundary is
where two plates meet. When two plates move towards each other
they form what is called a convergent boundary. Ocean crust is
made mostly of the iron rich rock known as basalt. Continental
crust is mostly composed of silica rich rock called granite.
From the 8th grade science text book chapter 9 page ____, the
following information was found. When an ocean plate and a
continental plate meet at a convergent boundary, one plate moves
under the other in a process called subduction. At a subduction
zone, the plate that sinks returns to the mantle where it heats,
melts, and forms magma.
__________________________________________________
_______________________________________________.
III.
IV.
Hypothesis:_________________________________________.
Materials and Procedures:
1. Use the scale to find the mass of each rock sample then record
it in the chart. Find the volume of the rock by using water
displacement. Start with 50ml of water. Place the volume of
the rock on the chart.
2. Determine the density of the rock.
3. Do all of one rock sample information one at a time.
4. Repeat for all the rock samples.
5. Find the Average density for the Basalt and the Granite.
6. Place the AVERAGE density on the board for the class data
chart information.
V.
Data
Ocean Floor
Basalt 1
Mass (g)
Volume(ml)
Density
Basalt 2
Basalt 3
+
+
Average
X
X
=
(Remember to add all three densities together and divide by three to
determine density. Use the correct unit of measurement for DENSITY.)
Continental Floor
Granite 1
Mass (g)
Volume (ml)
Density
Granite 2
Granite 3
+
+
Average
X
X
=
(Remember to add all three densities together and divide by three to
determine density. Use the correct unit of measurement for DENSITY.)
Class Data: Ocean Crust: Basalt
2
3
4
5
6
7
Average 1
8
9
10
11
12
13
14
Find the overall average of the class for Basalt_________________.
Class Data: Continental Crust: Granite
2
3
4
5
6
7
8
9
10
11
12
13
14
Average 1
Find the overall average of the class for Granite________________.
Questions:
1.
What is the average density of the basalt, which makes up
the ocean plate?_____________________.
2.
What is the average density of granite, which makes up the
continental plates?__________________.
3.
Based on the data collected in the lab which plate should
subduct into the mantle and be recycled back into magma?
VI.
Conclusion:
VII.
Clarifications:
VIII. Controls: (5)
IX.
Independent Variable:
X.
Dependent Variable:
XI.
Extensions: