EARTH & SPACE SCIENCE
CRUSTAL DENSITY LAB
Density & the Earth’s Crust Lab
You will be given three rock samples. Your task is to calculate the density of each rock sample. To do this, you will need to find the
mass of each sample. You will then need to find the volume of space each sample takes up. Then you will perform a calculation to
find the density.
PROCEDURES:
1. For each sample, write down what you can observe about the physical properties (size, shape, color, appearance, smell,
etc.).
2. For each sample, draw a quick sketch of your sample. Make your sketch accurate, especially in terms of shape,
appearance, and color.
3. Use the balance to find the mass of each sample. Record the mass in grams in your data table.
4. Use a 100 mL graduated cylinder to find the volume of each sample. To do this:
a. Fill the graduated cylinder part way to a number that is easy to read. You must have enough water to
completely cover the rock sample when you put it in but not so much water that the cylinder overflows or fills
above the measuring lines. Try to begin on an even number – 20, 30, 40, etc. – if you can.
b. Record the amount of water in the cylinder in the ‘before’ column.
c. CAREFULLY slide the rock sample into the graduated cylinder. Make sure the water covers the rock sample
completely.
d. Wait until the water settles and then record the amount of water after the rock sample has been added in the
‘after’ column.
e. Calculate the volume of the sample using this equation:
Volume = Amount after – Amount before
5. Calculate the density of each sample using the formula for density:
density = mass/volume or  = m/V.
DATA TABLE:
Granite (Continental Crust)
Basalt (Oceanic Crust)
Banded Iron (Deep Interior)
Written
Observations/
Description
Drawing
Mass of sample
(g)
Volume of
sample
(cm3)
Amount before:
Volume:
Density of
Sample
(show your
work)
Amount After:
Amount before:
Volume:
Amount After:
Amount before:
Volume:
Amount After:
Class Average Data Table:
Group
Density of Granite
(Continental Crust) Sample
Density of Basalt
(Oceanic Crust) Sample
1
2
3
4
5
6
7
8
AVG
PART 1 QUESTIONS: Answer the following IN COMPLETE SENTENCES.
1. Did your group’s measurements
agree with the class averages? In
other words, did the relative
densities of your samples agree with
the relative densities of the class
averages? If not, why?
2. List all the ways that you may have
error in this lab activity:
3. Did any of the groups have very
different densities for their samples?
If not, why not? If so, why might
they have gotten different results?
Density of Banded Iron
(Deep Interior) sample
PART 2 QUESTIONS: Answer the following IN COMPLETE SENTENCES.
1. Which rock has the highest density?
2. Which rock has the lowest density?
3. Examine the following cubes:
Cube A
Which cube is more dense? How do you know?
Cube B
3. One of the cubes represents
Granite. The other represents
Basalt.
Cube A represents ______________________. How do you know?
Cube B represents ______________________. How do you know?
Cube A
Cube B
4. The Earth’s crust is made up of two
different types – continental crust
and oceanic crust. Continental crust
is of granitic composition, meaning it
is made mostly of granite. Oceanic
crust is made mostly of basalt.
Which type of crust is more dense?
5. If a chunk of oceanic crust is
smashed into a chunk of continental
crust, one of them will slide
underneath the other. Which type of
crust will go under? Explain your
answer completely.