Science of NHL Hockey: Mass, Volume, and Density
Subject Area: Physics, Math
Grade Level: 9–12 (Physics)
Lesson Title: Mass, Volume, and Density
National Science Education Standards:
 Science as Inquiry: 9–12
 Structure and Properties of Matter: 9–12
Suggested Prior Knowledge: concepts of mass, weight, volume, and density; lab techniques of
measuring mass and volume
Purpose and Introduction: One of the “stars” of this video is the Zamboni®, the particular
brand of machine used by the National Hockey League (NHL) that smoothes the ice between
periods of a hockey game. A Zamboni weighs about 10,000 pounds empty, and travels about ¾
of a mile during each resurfacing. Before ice-resurfacing machines were invented, people
resurfaced the ice manually using scrapers, water hoses, and squeegees. The basic science
underlying the resurfacing action involves knowledge of solids, liquids, and gases. Students will
make connections to the physical properties of mass and volume of matter and the relationships
between of mass, volume, and density.
Key Vocabulary:
density—a measure of how tightly packed something is in a specific volume; the measure of
the quantity of matter per unit volume.
mass—the measure of the amount of matter in something.
volume—the measure of how much space something occupies in terms of height, width, and
depth; measured in cubic meters.
weight— the force of Earth’s gravity pulling on an object’s mass.
Objectives:
1. Students will measure the density of a solid (concrete brick, hockey puck, and ice), a gas
(exhaled air), and a liquid (water).
2. Students will design and carry out an investigation to make comparisons among the
densities of these substances.
Materials:
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Safety goggles
Balance
Centimeter ruler
150 mL graduated cylinder
Tap water
Rectangular concrete brick
Hockey puck
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Ice cubes with 30 cm lengths of thread passing through them
Metal washers, keys, or other weights
Spherical balloons
Procedure:
1. Help students visualize the ice-making process by giving them rulers. Encourage them to
draw a line that represents the floor of the rink. Then, direct them to add a second line
1/32 of an inch above the first. Point out that this is the thickness of the first layer of ice
that is painted. Encourage students to suggest reasons why such thin layers are used to
make up the surface, and why the ice is painted instead of the concrete. Also point out to
students that many resources call water vapor “steam.” Be sure students understand,
however, that water vapor, or steam, is invisible. The visible water commonly called
steam is composed of tiny condensed water droplets—liquid water.
2. Elicit suggestions from students regarding the key points made in the video about states
of matter—in this case, water. (The fourth state—plasma—is not relevant to this lesson.)
Discuss with students the physical properties of mass, volume, and density. Some
questions to guide discussion include the following:
 What is mass? How does it compare to volume?
 How can you describe the density of a substance?
 What are the differences between a solid and a liquid?
 What are the differences between a liquid and a gas?
3. Laboratory protocols should be followed, incorporating safety equipment. Goggles must
be worn at all times.
4. Guide students to design an investigation that is valid and that will allow them to observe
some of the physical properties of water and other substances. Work with students to
design procedures similar to those outlined in this lesson plan.
5. Some questions to help focus their plans and guide them include the following:
 How can you measure the mass of a solid (or liquid or gas) with the lab
equipment available?
 How can you measure the volume of a solid (or liquid or gas) with the lab
equipment available?
 How can you determine the density of a solid (or liquid or gas)?
6. Students should be familiar with measuring mass, as well as with linear dimensions. You
may want to review how to read a graduated cylinder. Remind students that the accuracy
of their results will be affected by how carefully they measure quantities in the lab.
7. Some procedures students might use include the following:
 Measuring the mass of a solid is a straightforward procedure with a balance.
 Measuring the volume of a regular solid requires careful use of the ruler and use
of the proper formula. (For a rectangular solid, the formula is volume = height ×
width × length.)
 Density is then calculated by dividing:
density of solid = (mass of solid)/(volume of solid)
 To measure the volume of an irregular solid, students can place the object in a
graduated cylinder that has a known quantity of water in it. (Ice is tricky, because
it floats in water, but freezing a thread into a cube makes submerging the cube
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possible. Use one end of the thread to tie on the weights. Use the other to lower
the weights into the water in the cylinder to take a “before” reading. Then lower
the ice until it is submerged and take an “after” reading within a few seconds.
Point out to students that the ice melts very quickly so accurate readings must be
taken quickly.)
 The volume of the hockey puck might be measured either by displacement or by
using the formula for a cylinder: π × radius2 × height.
 Determining the mass of a liquid requires two measurements. First, measure the
mass of an empty 150 mL graduated cylinder. Then fill the cylinder with a
specific volume of the liquid (50 or 100 mL) and measure its mass again. Subtract
the mass of the empty cylinder from the total mass. Students in this way obtain
both the mass and volume of a sample of a liquid. They can substitute these
measurements into the density formula:
density of liquid = (mass of liquid)/(volume of liquid)
 Determining the mass of a gas requires two measurements. First measure the mass
of a deflated balloon. Then blow up the balloon and measure its mass. Subtract
the mass of the empty balloon from the total mass.
 The ease of determining the volume of gas in a balloon depends greatly on the
balloon’s shape. If the balloon is spherical or cylindrical, use the formula for the
volume of the shape for determining the volume. If the balloon is irregularly
shaped, you might use the water displacement method. This would result in a
measurement slightly less than the actual volume, since submerging the balloon
will compress it.. Another method would be to insert a balloon into an open
container of known volume, and blow up the balloon until it fills that container. If
this method is used, the container would need to be included in the calculation of
mass.
 Students can substitute these measurements into the density formula:
density of gas = (mass of gas)/(volume of gas)
8. Encourage students to discuss what they observed in this investigation and to compare
their results to those of their classmates. The following are some topics to consider:
 How are the quantities mass, volume, and density related?
 What is the relation of the density of a solid to the density of a liquid in which it
floats? In which it sinks?
 What is the relation of the density of ice to the density of liquid water?
 How does the density of a gas compare to the density of a liquid or a solid?
9. Relate students’ work back to the video. Elicit from students that the first layer of ice that
is 1/32 of an inch thick is actually formed from a thinner layer of water. Students should
recognize that the volume of water required to produce the ice sheet is less than the
volume of the ice sheet itself. The video points out that 40,000 l of water expands to
43,600 l when it freezes. (You might need to remind students that 1 ml is equal to 1 cm3.
Point out to students that it is that volume of ice that still has a mass of 40,000 kg. Be
sure they understand that the volume of water is not equal to the mass of the resulting ice
sheet.) Have students use the density of ice (0.917 kg/l) to calculate how thick the layer
of water is that’s needed to make 1/32 of an inch of ice.
10. After the students have finished their investigation, try the following exercise. Have each
group put an ice cube in a graduated cylinder and record the water level. Also have the
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groups measure the highest point of the ice cube above the water level. Ask them to
predict what the water level will be after the ice melts. Let the ice melt, and have each
group explain why there is no change in water level. Then discuss the activity as a class.
Additional Resources:
 http://www.ajdesigner.com/phpdensity/density_equation.php
 http://www.zamboni.com/about/how-it-works/
 http://www.zamboni.com/about/fun-facts/
 http://www.mentalfloss.com/blogs/archives/55859
 http://ga.water.usgs.gov/edu/waterproperties.html
 http://entertainment.howstuffworks.com/ice-rink6.htm
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Student Worksheet for Investigation of Mass, Volume, and Density
Experiment Title: _____________________________Date: __________Name: _____________
Student Hypothesis: _____________________________________________________________
Materials:
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Safety goggles
Balance
Centimeter ruler
150 mL graduated cylinder
Tap water
Rectangular concrete brick
Ice cubes with 30 cm lengths of thread passing through them
Washers, keys, or other weights
Spherical balloons
Procedure:
Lab safety equipment should be used, and safety protocols followed.
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Data and Observations:
Analysis of Data: _______________________________________________________________
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Conclusion: ___________________________________________________________________
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