Name____________________________________Date_______________Period
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Mile-High Baseball
Purpose
Materials
To investigate the effect of air density on the flight of an object
• two
6 inch × 6 inch aluminum
foil squares
• stopwatch
• two sheets
of plain copier paper
Scenario
Denver, Colorado, is called “The Mile-High City” because it sits about one mile above sea
level. Denver is the highest city in the United States with a Major League Baseball team, the Colorado
Rockies.
The Rockies hit many more home runs during home games than during away games. You
might say the Rockies have the ultimate home-field advantage. The stadium where the Rockies play
has been called “the greatest hitter’s park in baseball history.” Home runs hit there travel farther than
home runs hit in other ballparks. There are even players who can hit home runs in Denver but
nowhere else.
The commissioner of Major League Baseball wants to know why it is so much easier to hit
home runs in Denver. Is it the result of gravity or air resistance? Is there anything that the league can
do to take away what some consider an unfair advantage? As a physicist and a baseball fan, you have
volunteered to answer the commissioner’s questions.
Initial speed
of ball (m/s)
35
40
45
50
The Effect of Altitude on Baseball Flight
Distance traveled Distance traveled
Distance traveled on
at sea level (m)
in Denver (m)
Mount Everest (m)
(elevation 0 m)
(elevation 1,609 m) (elevation 8,848 m)
72.9
77.2
94.5
85.3
91.0
115.2
96.9
104.2
135.7
107.7
116.5
155.8
Distance
traveled in a
vacuum (m)
123.1
160.8
203.5
251.2
Procedure
1. Gravity or Friction Discuss with your partners how both gravity and air density change as you
go higher in the atmosphere. Which do you think changes more? Explain.
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2. Share Your Ideas After discussing this with your group, share your answer with another team and
compare your reasons. When your teacher asks, share your ideas with the class.
3. Lessening the Impact As a baseball moves through the air, it pushes air molecules out of the
way, but the air also pushes back. The faster the ball moves, the greater the air pushes back. This
is called air resistance. Since Denver is a mile above sea level, its air is less dense, meaning there
is less air resistance. How can you decrease air resistance? Work with your team to think of some
possibilities. Jot your ideas down below.
Name____________________________________Date_______________Period
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Procedure (continued)
4. Test Your Ideas Time how long it takes for
a sheet of paper to fall to the floor. Record
the time in the table provided. Next, change
the shape of the paper in a way that you
think will make it fall faster. You cannot
change the mass of the paper. Drop the
paper from the same height as before, and
record the new fall time.
Object
paper
altered paper
foil
altered foil
Fall Time
5. Does the Material Make a Difference? Repeat Step 4 using a sheet of aluminum foil and record
your results.
Conclusion
Let’s see what you learned about how air density affects an object’s flight.
1. Which is more likely to affect a baseball hit in Denver: decreased gravity or decreased air
density? Explain.
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2. Why is the air less dense in Denver?
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3. Why do you think less air density causes the baseballs to travel further?
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4. How do you think home runs would be affected at a baseball stadium that was located below sea
level? (Hint: Below sea level means the altitude is lower than the altitude of the surface of the
ocean.)
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