CHAPTER 3 LAB 2: DETERMINING DENSITY
PURPOSE: Make measurements in lab and use them to determine the density of a variety of substances.
SAFETY: Wear goggles. Use caution with glassware. Return materials to their starting locations.
BACKGROUND:
The DENSITY of an object represents the ratio between the amount of material in a body (mass) and the
amount of space it takes up (volume). In other words, an object’s density identifies how many grams of
material are packed into each cubic centimeter of space.
NOTE:
The mass of any object is a physical quantity that represents the amount of matter in the object. Mass is
normally measured using a mechanical device that equates the mass of some object with known “standard
masses”. An electronic platform balance, equal-arm-balance (double pan), or a multi-beam balance (single
pan) may be used, where masses can be measured with accuracy to the nearest 0.1 gram. Mass is measured in
terms of grams or kilograms.
The volume of an object is a physical quantity representing the amount of space the object takes up.
The volume of RECTANGULAR or block shaped objects can be found by multiplying length, width, and
depth measurements, or V = l · w · d.
The volume of CYLINDER shaped objects can be found using the formula, V = pi · r2 · h
The UNITS of volume for SOLID objects are “cubic inches” (English) and “cubic centimeters”
(Metric). “Cubic” refers to the fact that every object has THREE DIMENSIONS that are multiplied together.
The volume of LIQUID and GASEOUS substances can be found by measuring the dimensions of the
container that holds them. Often, a liquid’s volume is found by poring the liquid into a measuring cup or
graduated cylinder that is marked in units of “ounces” (English) or “milliliters” (Metric).
The dimensions of length, width, depth, or diameter of an “irregular” object, such as a rock, are not
uniform or easy to measure, so the usual formulas can not be used. Instead, the object’s volume is found by
using the “water displacement” method. The units of volume for the irregular solid using this technique are
“cubic inches” and “cubic centimeters”.
Density 
amount of material
space taken up
Density 
Mass
Volume
D
M
V
The UNITS for density are, therefore,
Grams per cubic centimeter – g/cm3 – for solids and gases
Grams per milliliter – g/mL – for liquids

Procedure
(A) Density of a Wooden Block
WRITE THE NUMBER AND LETTER OF YOUR ASSIGNED BLOCK IN THE DATA TABLE BELOW.
1. Record the mass of the wooden block after placing it on the electronic pan balance.
2. Record the volume of the block after measuring its dimensions in centimeter units using a metric ruler, then
using the appropriate formula.
3. Calculate the density of the block using the formula, D = M/V. Units should be g/cm3.
Don’t forget significant figures!
OBJECT
Wooden
block letter
and #____
MASS
________g
FORMULA
M
D
V
VOLUME
=
L
x
W
x
D
_______ cm3 = ________cm x ________ cm x _______ cm
WORK
DENSITY
TYPE OF WOOD
Listed below are the different types of wood used in lab by other students, including their accepted density:
TYPE OF WOOD
Arbor vitae
Yellow pine
Black walnut
Red oak
Lignum vitae
DENSITY (g/cm3)
0.38
0.39 to 0.41
0.56 to 0.63
0.74
1.280 to 1.370

(B) Density of a Metal Cylinder
WRITE THE NUMBER OF THE METAL CYLINDER ASSIGNED IN THE DATA TABLE BELOW
1. Use the quad beam balance to measure the mass of the metal cylinder.
2. Using a Vernier Caliper, measure the diameter and height of the cylinder in centimeter units.
.
3. Divide the diameter in half, square it and record it as the (radius)2 in the equation below.
4. Use the formula, V = pi · r2 · h, to calculate the volume of the cylinder.
5. Calculate the density of the cylinder using the formula, D = M/V. Units should be g/cm3.
Don’t forget significant figures!
OBJECT
Metal
Cylinder
#____
MASS
________g
FORMULA
M
D
V
VOLUME
=
pi
x
r2
x
h
_________cm3 = _________ x ___________ cm2 x ________ cm
WORK
DENSITY
TYPE OF METAL
PERCENT ERROR
Listed below are the different types of metal used in lab by other students, including their accepted density:
METAL
DENSITY (g/cm3)
Aluminum
2.70
Iron
7.87
Copper
8.96
Brass
8.47

(C) Density of a Pebble
WRITE THE NUMBER OF YOUR ASSIGNED PEBBLE IN THE DATA TABLE BELOW.
The volume of an irregular object, such as a pebble must be measured indirectly using the method of “water
displacement”.
1. Fill a graduated cylinder to the 15-mL mark. This represents the original volume of water (VW). Record the
volume in the table below.
2. Drop a pebble into the water, and observe the rise in water level. The pebble has pushed aside or has
“displaced” a volume of water equal to its volume. The new water level represents the volume of water plus the
volume of the pebble (VW+P). By subtracting the original volume of water (VW) from the new volume of water
plus pebble (VW+P), the volume of the pebble alone (VP) can be obtained. Record this value on the data table.
Note that the volume of the pebble is initially recorded in terms of milliliters (mL). The volume of solid
objects, however, should be expressed in terms of cubic centimeters (cm3). The useful rule, 1 mL = 1 cm3, can
be used to make the conversion.
4. Use the quad beam balance to measure the mass of the pebble. Record its mass in the table below.
5. Calculate the density of the pebble using the formula, D = M/V.
OBJECT
Pebble
#_______
MASS
VOLUME(W+P) - VOLUME(W) = VOLUME(P)
_________ g
FORMULA
M
D
V
_______mL
WORK
-
_______mL = ________mL
_________cm3
DENSITY
TYPE OF PEBBLE
Listed below are the different types of metal used in lab by other students, including their accepted density:
Pebble Type
Sulfur
Sandstone
Topaz
Galena
Density (g/cm3)
1.9 to 2.0
2.4 to 2.8
3.5 to 3.6
7.2 to 7.6

(D) Density of water
1. Use the quad beam balance to measure the mass of an empty 25-mL graduated cylinder, M(CYL). Record this
value in the data table below.
2. Add exactly 15.0 mL of water to the graduated cylinder, making sure the meniscus is on the line.
3. Use the balance to measure the mass of the graduated cylinder plus water, M(CYL + W). Record this value in the
data table below.
4. Use the formula, M(CYL + W) – M(CYL) = M(W), to determine the mass of the water alone. Record this value in
the data table below.
5. Calculate the density of your sample of water using the formula, D = M/V.
Your instructor will tell you the accepted value for the density of water at room temperature. Use this to
determine the percent error for your measurement.
OBJECT
water
FORMULA
M
D
V
MASS(CYL + W) – MASS(CYL) = MASS(W)
________ g - ________ g = ________ g
WORK
DENSITY
VOLUME
__________mL
PERCENT ERROR
POST LAB QUESTIONS
1. What is the difference in accuracy and precision between the quad beam balance and the electronic pan
balance?
2. Explain any sources of error that may have occurred when making your measurements.
3. Why is “cm3” considered a derived unit? What other units in the lab are also derived units?
4. What advantage is there in using a Vernier caliper during the determination a cylindrical solid’s volume?
5. What happens to the density of a substance as the temperature increases? How is water an exception to this
generalization? Explain.
HAND IN THESE ITEMS:
The following items must be TYPED and handed in FOR EACH GROUP: data tables for each section, all
calculations and the answers to the questions at the end of the lab. DUE ON __________________.