ESS Unit 3
Name _____________________________ Period____
`Density of Earth’s Rocks
In this investigation you will compare the densities of four of Earth’s different
rocks/minerals that are found at different locations (depths). Then construct a model that
demonstrates their location in Earth using their densities.
First, hold the rocks in your hand and predict which rock has the highest density and which
rock has the lowest density.
Lowest density
Highest density
Materials: graduated cylinder, scale, samples of the following rocks or minerals (be sure
that they will fit inside the graduated cylinder): granite, basalt, peridotite (or the minerals
olivine and pyroxene), iron meteorite, magnetite or iron.
Procedure: The density of an object relates its mass to its size. Density = Mass / Volume.
1. Use a balance or scale to measure the mass of an object.
2. To find the volume, fill a graduated cylinder with a known volume of water.
SLIDE the rock sample SLOWLY into the water in the cylinder.
The difference in water levels before and after is equal to the volume of the object.
Rock sample
Granite
Basalt
Peridotite,
pyroxene, or
Olivine
Iron
meteorite,
Magnetite or
iron
Mass
(.01g)
Volume(before)
(0.1 ml)
Volume(after)
(0.1 ml)
Final Volume
Difference in
water level (ml)
Density:
m/v
(g/cm3)
CLASS AVE.
Density
(g/cm3)
ESS Unit 3
Name _____________________________ Period____
1. Using their densities, label the location of the rocks on the Earth diagram below.
Include the density and rock name for each layer.
g/cm3
Mountain and continental rock
name
g/cm3
Ocean floor rock
Earth’s mantle layer
name
g/cm3
name
Material in the center
of Earth
2. When the Earth was a molten planet early in its formation, a process called
differentiation or sorting occurred.
Use the densities of the rocks to write a hypothesis as to which rocks would be sorted
toward the center of the planet and which would be nearer to the surface.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
3. Two of Earth’s rocky layers of crust are colliding, one is made of granitic rock and the
other is basaltic rock. Using their densities, explain which one would subduct under
the other and which will be forced on top?
______________________________________________________________________
______________________________________________________________________
4. Average densities of the surface rocks granite and basalt: ____________g/cm3
The average density of the entire Earth is about 5.5 g/cm3
Are the surface rocks more or less dense than the Earth’s density? ______________
What does this suggest about the density of material in the center of the Earth?
ESS Unit 3
Name _____________________________ Period____
30
25
20
15
10
5
0
Mass (grams)
35
40
45
50
55
Plot the data and Label the Density of the 4 Earth’s Rocks
0
1
2
3
4
5
6
VOLUME (cm3)
7
8
9
10
11
12