Grade Level: 6th to 8th; Type: Physics
This project determines if corked bats truly make a ball travel farther than wooden bats that haven't been altered.
- What are two ways a batter can increase the momentum of the bat?
- How does the speed of a bat affect momentum?
- How does the weight of a bat affect momentum?
A bat is "corked" when the end of it has been drilled out and the hole created is stuffed with cork. The bat is then capped off so that it looks as if it hasn't been altered. Cork is thought to make the bat lighter, allowing the batter to swing faster, providing more momentum. The more momentum a batter has with a bat, the farther we would expect the ball to go when it's hit. However, corking can also decrease the weight of a bat, decreasing momentum. Does the extra speed of the swing make up for the lighter weight?
- Two identical bats
- Drill with a ½ inch bit
- Wood vise
- Cork sheeting
- White glue
- Permanent marker
- Ball tee
- Tape measure
- Pen and/or pencil
- Lab notebook
- Choose one bat to be corked. Clamp the bat in the wood vise. Mark the center of the wide end of the bat. Use the hammer and punch to dimple the wood so that the drill bit won't slip when starting. Note: Have an adult drill a ½ inch in diameter hole, no more than 6 inches deep. Make sure to drill straight along the long axis of the bat.
- Fill the hole with the cork. Pack it tightly.
- Use a permanent marker to label the bat that has been corked.
- Cap the end of the bat with a wooden disk and glue.
- Let the glue dry overnight.
- The next day, you can perform the test. You'll want to hit 25 balls with each bat, alternating bats with each swing. Attempt to swing at the same speed every time. You'll need to measure the flight distance of each ball hit and record it in your notebook.
- Analyze your data. Average the distances of the balls hit with the corked bat. Then average the distances of the balls hit with the unaltered bat. Which bat gave the best results? Why do you think that particular bat had the better results? You can graph your data to illustrate your reults.
Terms/Concepts: mass; velocity, momentum, diameter, speed, distance