# What Comes Down Must Go Back Up

## Introduction

This experiment was about the physics of balls and how different motions affected them. Surfaces of the balls also played a factor. The purpose of this experiment was to find out how these different balls bounced on these different material surfaces. The purpose was to see how someone could use these results in real life sports and take advantage of how the balls bounced on the different surfaces in sports like soccer or basketball. The hypothesis was: “A smaller ball will bounce higher while a larger ball will bounce short and with less force.” This hypothesis meant that smaller balls like golf balls or tennis balls will bounce higher yet require more force while larger balls like basketballs will bounce a shorter height but require less force to bounce. This experiment was done because it was needed to know how to better play sports and use these things to the best of their advantage. With the knowledge gained from the experiment, it was hoped that we would learn how to best utilize this data to our advantage.

## Hypothesis

If you bounce a tennis ball onto concrete floor, then it will be the ball that bounces the highest.

## Purpose/Objective

The purpose of this experiment is to test the different types of balls on different types of ground.

## Parts of the Experiment

Dependent Variable: The height of drop

Independent Variable: The type of ball

Control: Time of Day

Experimental group: Type of ground

Factors held constant: measurement, height of drop

## Materials

For materials, the experiment needs:

• A golf ball

• A tennis ball

• A softball

• A football

• A measuring stick

• Grass ground

• Concrete ground

## Procedures

1. First find a place to perform experiment

2.Set up materials at place

3.Create a graph and table to record and graph data

4. Start experiment by dropping each of the balls on grass

5. Repeat step 4 for a total of 3 trials.

6. Drop the balls again on concrete

7. Repeat for a total of 3 trials

8. Record data on to your table and calculate mean and ttest.

## Calculations

Manipulated Data:

Grass:

1. Trial 1-

Mean-4+10+2+17+11=44/5=8.8

Variance:(4-8.8)^2+(10-8.8)^2+(2-8.8)^2+(17-8.8)^2+(11-8.8)^2=142.8

Standard Deviation=142.8*(1/5)=28.56 squareroot(28.56):5.34

Concrete:

2. Trial 2-

Mean- 16+22+37+14+30.5=23.9

Variance:(16-23.9)^2+(22-23.9)^2+(37-23.9)^2+

(14-23.9)^2+(30.5-23.9)^2=379.2

Standard Deviation:379.2*(1/5)=75.84 Squareroot(75.84)=8.7

## Conclusion

The experiment expressed that the hypothesis that smaller balls bounce higher than larger balls because of greater amounts of force on most surfaces is true, but it is also wrong. Larger balls bounce much higher on surfaces that are not totally solid and have many varying factors, like grass. On grass, one of the largest objects, the football, bounced the highest, however this could have been easily because of the object and the way it bounces. The height of the balls bouncing depends on the surface of the solid it is bouncing on, and for objects like the golf ball and basketball, this is more easily seen as compared to the football, which has not much of a difference from grass and concrete and generally stayed at bouncing the same height.

## Analysis

The claim for this experiment is that I have observed that when you drop a tennis ball on the surface of a concrete it will the height of the bounce up will be higher than all the other. As what I have observed I have seen that most of the other balls have more mass than others. The data shown in the statistical analysis and the graphs show that the tennis ball is the one that ended up bouncing the highest.

The science experiment was fairly easy to follow. Many people believe that when a ball bounces on concrete it bounces higher than a ball that bounces on grass. The results showed that this fact is true. Only one result showed that the balls bouncing on the grass bounced higher than the balls on the concrete. The golf ball and the basketball had the biggest difference between the height of the ball bouncing on the grass and the height of the ball bouncing on the concrete.

## Sources of Error and Inaccuracies

There are many different factors that could have created errors in the experiment though. The weather could have affected the wind speed that changed the height of the ball and how it moved. The heights dropped could not have been from exactly the same height and could affect the bounce height. The data was generally the same. The experiment could have been changed by instead experimenting in a weather where there is no current wind as to better avoid any weather resistance. The factor of the football being shaped differently and affecting its air movement was also not taken into account.

## Application

Adidas and other sporting goods companies can base off this information and make new balls that are less buoyant for actual soccer and sports players to do better when they play. Many other people will also like this because it affects the way they play and they will be able to play better with the more efficient ball that has better control and force in it.

## Improvements

There can be a lot that is mistaken throughout the course of a experiment. I could have used more confidence in my experiment so that I would be more accurate and not be so sloppy. This may have caused a mistake or two. Everyone can improve in forming his or her experiment to make it more interesting and not so boring. One thing that I could have improved the most is not to use so many variables at once and do better at keeping it simple but still interesting.