Baseballerz

By: Rachel & Mary

Lab Goal: To determine the appropriateness of each of type of ball used for different games of baseball. We did this by testing the impulse to see how much force a player would experience by using the certain ball, and we timed each fall to see if there is a difference in speed between balls.

__Supplies:__
 * Whiffle Ball
 * Tennis Ball
 * Baseball
 * Softball
 * Timer
 * Mass Scale
 * Meter stick
 * String

__Procedure:__
 * 1) Find the mass of each ball and record in data section of your lab notebook. (Note: mass is found in g, so move decimal point 3 places to left to find kg.)



2. Drop each ball from the top of the pit stairs and measure the time. Take three times, and record all values in data. Take the 3 values and find an average value. (t1+t2+t3)/3.

media type="file" key="video.3gp" width="300" height="300" 3. Measure the height of where the ball was dropped from. Do this by taking a string and having one person stand at the bottom of the pit, and another person standing at the top. Throw the ball of string up, and have each partner pull it tight until there is a tight resistance. Take the string back and measure it using a meter stick. Record height in data.

4. Using the mass found from the scale, and knowledge of kinematic equations, find the impulse of each ball. To do this, use the equation impule=m(vf-vi). The initial velocy is 0 because it starts from rest. We know the mass from measuring, but we need to find the final velocity. To do this, you would use the equation vf^2=vi^2+2ad. We can plug in 0 for the initial velocity. Acceleration is 9.8 because it is dropped vertically. Distance is what was measure with the string and meater stick. Therefore, all we have left to solve for is vf. Find this for each ball and record it in notebook. Then take this value and plug it into the impulse equation stated earlier, and record in notebook.

5. Make conclusions based on the data.

__Data:__
 * Time taken to drop for each ball: (in minutes and seconds)**
 * =  || Tennis || Wiffle || Softball || Baseball ||
 * = T1 ||= 1:15 ||= 1:30 ||= 1:05 ||= 1:05 ||
 * = T2 ||= 1:14 ||= 1:27 ||= 1:02 ||= 1:10 ||
 * = T3 ||= 1:14 ||= 1:35 ||= 1:04 ||= 1:16 ||
 * = Avg. ||= 1:15 ||= 1:31 ||= 1:05 ||= 1:11 ||
 * Mass of each ball:**
 * || Tennis || Wiffle || Softball || Baseball ||
 * Mass (g) || 57 g. || 26 g. || 192 g. || 141 g ||
 * Mass (kg) || .057 kg || .026 kg || .192 kg || .141 kg ||
 * Height from top of pit to bottom:** 5.03 meters

__Calculations:__
 * Find final velocity**: (Note: for each ball it will be the same because it is the same height and acceleration)

vf^2=vi^2+2ad

variables: vf=? vi=0 a=9.8 d=5.03 meters

work: vf=sqroot(2*9.8*5.03) vf=9.929 m/s

impulse=change in momentum= mass*(vf-vi)
 * Impulse of each ball: **

variables: vi=0 vf= 9.929 m/s mass=see data table for each ball (in kg)

work: Tennis: .057(9.929) = .566 kg*m/s Whiffle : .026(9.929) = .258 kg*m/s Softball : .192(9.929) = 1.906 kg*m/s Baseball : .141(9.929) = 1.4 kg*m/s

__Conclusion:__ The experimental results led us to believe that both girls and boys should play with baseballs; while younger kids should play with whiffle balls. When we timed how long it took each ball to fall from the top of the pit, we found that all four balls took similar times to fall. We expected before the conduction of the experiment that the times would be different. However, the data that we ended up getting makes sense based on our knowledge of projectiles. Therefore, the time it takes to fall would not be a factor in determining appropriateness of a ball for its use. This led us to approach our issue in a different way. We determined that the best way to answer our question was to examine the impulse of each ball.

The massing of the ball, in addition to our knowledge of velocity, allows us to find the impulse. Our results showed that a softball had a higher impulse than a baseball. We found this interesting because typically girls play with softballs, while boys play with baseballs. We understand how since the baseball has a smaller surface area, that the impulse is compressed into a smaller volume. Therefore, the impact it would have on a person would be greater. Softballs can be useful because they are padded, and are a larger size. Therefore the impulse is greater spread over its surface area. However, we believe that both boys and girls should play with baseballs. One yahoo user*, "Maber" prefers to play with a baseball because "the feel of the [ball] ... is better. They are smaller and easier to control. Softballs are big and cumbersome." We agree with Maber. From personal experience, we have played with both baseballs and softballs. We prefer the feel and hit of a baseball; it is much easier to hit, and it doesn't hurt //that// much to get hit by one. Our results show that the impulse of a softball is higher. Girls' leagues can find other ways to add safety to the game, but in the end, the impulse of a baseball is less. Both softballs and baseballs can cause injury, but the fact that the baseball is less massive makes it have a smaller impulse when it comes into contact with a human. For the same reason, we believe that young kids should use a whiffle ball rather than a tennis ball. When first learning the game, throwing, catching, and hitting the ball can be difficult. Many kids play pick up games of backyard baseball games. So, their ball of choice should be the wiffle ball. The impulse of a wiffle ball is the lowest out of all four balls; therefore it would be less likely to break windows or other items. According to livestrong.com**,** "Wiffle ball allows children to practice pitching and hitting in small backyards without having to worry about hitting the ball too far or breaking windows."

We realize the fact that there may be error(s) in our results. Some of these could include, but are not limited to: recording the accurate mass, recording the accurate velocity, and timing precisely.

WE ARE BALLERZ!


 * Sources:**
 * []**


 * []