Purpose

To investigate the relationship between bat materials, their effectiveness, and their safety.

Materials Fundamentals - What is Density? Skills - How is Density Measured? balance graduated cylinders wood sample aluminum sample index card

High School Baseball Photo Courtesy AVSports

Officials in Massachusetts have decided that aluminum bats can be dangerous. A ball hit by an aluminum bat has a greater speed than a ball struck by a wooden bat. As a result, Massachusetts's officials have banned aluminum bats from high school tournaments. The ban is only for this year, but they have recommended that aluminum bats be banned from all high school games in the future.

Before final action is taken, the governor wants more research. Do aluminum bats have more energy? Do they give up more of their energy to the ball than wooden bats do? If so, why? The governor wants real numbers from real scientists.

There is no question that aluminum bats cause greater ball speed. You and the other scientists who have been hired to work on this problem have decided to start with the basics. You will determine the density of the two materials. Compare the density of wood with the density of aluminum to explain whether you think density affects the difference in ball speed. You will also recommend further testing if needed.

Procedure

Read Fundamentals - What is Density? and Skills - How is Density Measured? Then, design and conduct an experiment to compare the density of wood with the density of aluminum.

Conclusion

Once you have collected and analyzed your data, write a postcard to the governor's office telling what you found. Did you discover a significant difference in the densities of the two bat materials? Is there a connection between material density and ball speed? Is that the only factor that can explain the difference between aluminum bats and wooden bats? List other things that should be tested next.

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This activity was developed by the Event-Based Science Institute with generous support from the Cal Ripken, Sr. Foundation. A teacher version of this and all other baseball/physics activities is available free from the EBS Institute. This activity was written by Nancy Ehrlich, science teacher at Cabin John Middle School, Potomac, MD.