Density
Matter and Energy
Student Guide
Density
Part I: How Dense Is It?
Everything on Earth is made of matter. Matter is anything that has mass and takes up
space. Matter is as simple as a single element or as complex as the entire planet. In
science, an amount of space is called volume. Matter can be any substance in the gas,
liquid, or solid state.
When we describe matter, we usually think of the physical properties of the object, for
example: color, smell, taste, feel, volume, and mass. Another important physical
property, density, is used to describe matter as a ratio, or number comparison, of the
matter’s mass (m) to its occupied volume (v). The more matter squeezed into the space,
the denser the substance will be. A small piece of candy is denser than a handful of
cotton balls because the candy has more mass contained with the occupied space
(volume). A small piece of candy would still be denser than a bag full of cotton balls
because density describes how much mass is contained within a specific volume.
Density is a physical property that relates to the amount of matter to a certain amount of
space. How do you think this physical property is measured? Density measures how
much mass is in a certain space, so density is measured in mass and volume. The
scientific definition of density is mass per unit volume.
As you think and learn about density, consider the following questions:
Does a part of a substance have a different
density than the whole piece?
How can the density of irregularly shaped
objects be calculated?
Record your ideas about these questions in Part I of your Student Journal sheet.
Density
Matter and Energy
Student Guide
Part II: Density and Units for Solids with a Regular Shape
To calculate density, divide the mass of the matter by the volume that it takes up. Here
are the equations:
Density:
Mass
OR
D=
m
Volume
v
In order to calculate the density of matter, you must use units of both mass and
volume.
For solid materials you use grams (g) for mass, and cubic centimeters (cm3) for
volume.
For liquid materials you use grams (g) for mass, and milliliter (mL) for volume.
The letter D represents density.
For solid matter:
D=
g
Cm𝟑
For liquid matter:
D=
g
ml
The volume of a regularly shaped object is determined by measuring the l (length) x w
(width) x h (height) of the substance, resulting in a measurement in cubic centimeters
(cm3).
Density
Matter and Energy
Student Guide
Materials
One Petri Dish for each lab member
Triple beam balance
One Starburst for each lab member
Ruler
Procedure A: Calculate Density of a Solid with a Regular
Shape
1. Use a Post-It note to label a Petri dish for each lab member.
2. Next, use a triple-beam balance to find the mass of each
labeled Petri dish. Record the mass in your Student Journal.
3. Take your Starburst and remove the wrapper.
4. Now, each group member will place their Starburst in their
labeled and massed Petri dish.
5. Determine the mass of the Starburst plus the Petri dish by placing the Petri dish with
the candy in it on the triple beam balance. Record on Student Journal #2
6. Next, find the mass of just the Starburst. (Subtract the mass of the Petri dish to
determine the mass of just the Starburst and record the measurement in your
Student Journal)
7. Carefully measure the length (L), width (W), and height (H)
in centimeters of the candy and record it in your Student
Journal.
8. Use the volume formula (L x W x H = V) to calculate the
volume in cm3 for the piece of candy.
9. Use the density formula to calculate the density of the candy.

D =
Mass (grams)
Volume (cm3)
10. Compare and record the measurement and density results of your candy with
your lab partners’ candy on the data table in the Student Journal.
Density
Matter and Energy
Student Guide
Part III: Density and Units for Solids using Displacement
You have determined the density of a regularly shaped object by using a piece of
candy and using the volume formula of V = l x w x h and then measuring the mass of
the candy in grams. You probably found that your original candy density calculation
varied somewhat from that calculated by other students. It is very likely that your
candy are slightly irregular shapes, which makes it challenging to determine volume
using a ruler.
When calculating density, it is very important to be as precise as possible. You will be
able to obtain a more precise volume by using a different technique, the
displacement method. The volume of a solid can be obtained using the displacement
method by slowly immersing the object into a graduated cylinder partially filled with
water. The object will always displace an amount of water equal to its volume.
Displacement – a way to measure the volume of a solid by placing it in a known
volume of liquid.
Part III: Density and Units for Solids using Displacement, continued
Procedure B: Calculate Density of a Starburst using the Displacement Method
1. Pour 15 mL of water into a 25 mL graduated cylinder. Set the cylinder on the lab
table and read the exact number of mL (remember to read the graduate scale at
eye level at the base of the meniscus). Record this reading in your Student
Journal in the blank labeled initial Volume of Water.
2. Slightly tilt the graduated cylinder. Slowly allow the Starburst to glide down the
side so that it gently slides into the water. Place the cylinder on the lab table and
read the new measurement on the graduate scale (Again at eye level and at the
base of the meniscus). Record this second measurement in your Student Journal
in the blank labeled Final Volume of Water.
3. To obtain the volume in the graduated
cylinder displaced by the Starburst,
subtract the initial measurement (from
step 1) form the final measurement
(from step 2).
4. Re-calculate the density of your
Starburst using the displacement
method to determine volume. Record
your results in Part III of your Student
answer the questions.

1 mL
Journal and then
1 cm3
D = Mass (grams)
Volume (cm3)
*Remember: You are using the volume you found from the displacement
method for the volume in the density formula and the mass of the Starburst that
you previously calculated.
Note: 1 cm3 = 1 mL
Density
Matter and Energy
Student Guide
Part IV: Comparing the Density of Substances
You have used two procedures to calculate the density
of your Starburst. First you measured the length, width,
and height of the cube with a ruler to determine the
volume. This method is frequently used for regularly
shaped objects. Then you used the displacement
method to determine the volume. This method is
frequently used for irregularly shaped objects that are
not easily measured accurately with a ruler.
Next determine the density of an irregularly shaped
Starbursts piece by using the displacement method.
Procedure C: Calculate Density of an Irregular
Solid using the Displacement Method
1. Use the Starbursts scraps to make an irregularly
shaped Starburst sculpture.
2. Use the triple beam balance to measure the mass
of your sculpture and record in your Student Journal.
3. Using a 100mL graduated cylinder, pour 20 mL of water into it (Be sure to read the
meniscus).
4. Tilt the graduated cylinder back and slowly place the irregularly shaped Starburst
in.
5. Use the displacement method to measure the volume of your Starburst and record
in your Student Journal. To obtain the volume in the graduated cylinder displaced
by the Starburst, subtract the final measurement (from step 4) from the initial
measurement (from step 3).
6. Use the density formula to determine the density of your Starburst sculpture and
record the density in your Student Journal.
D = Mass (grams)
Volume (cm3)
Density
Matter and Energy
Part V: Calculating Density of Liquids
Next you will determine the density of water. You will use the same process as you did
for the irregular solids.
Procedure:
1. Gather your materials: graduated cylinder, triple beam
balance, 150 mL of water, and a plastic cup.
2. Find the mass of an empty and dry graduated cylinder
using a triple beam balance. Record in The Density of
Water data table in your Student Journal.
3. Pour 50 mL of water in the graduated cylinder and find the mass using the triple
beam balance. Record the mass of the filled container in the
data table.
4. Subtract the mass of the empty container (step 2) from
the mass of the filled container (step 3) to get the
mass of just the water.
5. Record the volume you massed in the volume column of the data table.
6. Calculate the density of the water in the graduated cylinder using the density
formula.
D = Mass (grams)
Volume (cm3)
7. Repeat the process with 100 mL of water in the plastic
cup. Instead of massing the graduated cylinder, you will
use the plastic cup. Record all data in your Student
Journal.
Complete Part V in your Student Journal, then answer Reflection and Conclusion questions