Bat In Action Physics Zachary Senchak 10 th Grade New Castle High School

Observation Growing up from playing baseball from an early age I noticed how from year to year the type of ball I used changed. The difference between each baseball will effect how far or how fast the ball will reflect off of the bat. This led me to my question which is will the different type of baseball have an effect on the rebound height bounced off of the bat?

Research The sweet spot on a baseball bat is the location which produces maximum batted ball speed, and the location where maximum energy is transferred to the ball. The sweet spot is located in the middle of the barrel. Tee-Ball Baseball- a baseball that is very soft. It contains more rubber than any other baseball. Pony League Baseball- a baseball that is durable and has a hard outside shell covered in leather. Official League Baseball- a baseball that is larger than most and is very durable and hard. It contains a string like straw wrapped around a solid ball in the center of the baseball.

Research (Cont.) BBCOR- stands for "bat - ball coefficient of restitution,“ which measures how efficient the ball rebounds off the bat. This means the velocity before the impact of the bat and ball. BBCOR bats are designed to achieve wood-like performance in non-wood bats.

Hypothesis I think the tee-ball will have the highest rebound height off of the BBCOR bat because it is the ball that tends to have more recoil when hit with a bat.

Materials List 50 centimeter cylinder pipe 3 Baseballs (Tee-Ball, Pony League, Official League) 1 Baseball Bat (BBCOR) Metric tape measure 2-two hole straps 4 screws 30 centimeter piece of velcro Video Camera

Controls and Variables Controls - cylinder pipe drop height baseball bat tester video camera wall Independent Variable- type of baseballs Dependent Variable- rebound height of the baseball

Test Procedures 1.Place the tape measure on a smooth wall by taping each side as tight to the wall as possible avoiding bumps and creases. 2.Put and hold the cylinder pipe Ninety centimeters up the wall. The top of the pipe should be at the 90 centimeter mark. 3.Take the two hole straps and place one at the bottom and one at the top of the pipe. Screw in the screws tightly so that the pipe is steady. 4.Place a strip of velcro on the ground underneath the pipe. Then place the other velcro strip on the bat’s barrel. Place the bat’s barrel on the velcro. The bat should stay still. The middle of the barrel should be right under the pipe opening.

Test procedure 5. Set the high-speed video camera were the lens is right above the bat. The angle of the camera should only see the bat and the tape measurer behind it. 6.Turn the video camera on and record. 7.Release the baseball at the top of the pipe. The baseball should not be inside the pipe when dropped. 8. After the baseball bounces off the bat, stop recording. 9. Play the video and find the highest point the ball has bounced off the bat and record results. 10. Repeat steps times. 11. Repeat steps 4-10 for each baseball.

Data Sample Tee-Ball (cm) Pony League (cm) Official League (cm) Avg. 42Avg. 34Avg. 36

Error Analysis The results have supported my hypothesis. Possible errors: The probability of the ball hitting the bat on its laces.

Conclusion Hypothesis restated: - I think the tee-ball will have the highest rebound height off of the BBCOR bat because it is the ball that tends to have more recoil when hit with a bat. My data supported my hypothesis: - The Tee Balls average height was 42 cm. - The Pony League baseballs average height was 34 cm. - The Official League baseballs average height was 36 cm.

Future Research If I were to do this experiment again, I would: Use more then one bat to see the change of rebound height from each different baseball bat. Change the drop height to get different results but see if the ratios from this experiment are equivalent to the changed height. Use more baseballs to get more data calculated.

Sources Cited baseballs/