IF the amount of air pressure is changed in a soccer ball THEN the higher the psi in the ball, the higher it will bounce BECAUSE the ball will be harder against the hard ground. The reason for this is because the more air that is pumped into the ball, the more energy particles exist in the ball and the less space there is for them to move around.

Background Research \~ How to Measure Rebound

What is rebound? First of all rebound is the height recorded of the first bounce it is critical that  you measure the rebound of the FIRST bounce. Next you must video the dropping of the ball so that you can more easily record the rebound it is easier if You use a slo-mo video. Lastly make sure the camera is on a tripod at the same consistent height. In conclusion rebound is a way to measure bouncing balls.

Background Research\~ Gravity

To start, on earth gravity pulls objects toward the center of earth. This is what makes objects fall. Next, the longer an object falls the faster it goes. An example of this is when a pencil is dropped from 5cm then 15cm it goes much faster. Finally, in this experiment to accurately measure how the air pressure changes the rebound height the drop height MUST be consistent. To sum it up dropping it from the same height is super important. 

Background Research\~ is there a Perfect Pressure

To begin, the perfect pressure will vary for every player. First of all, some players prefer softer balls even when harder balls have a more consistent rebound height. Secondly, the perfect pressure will vary based on the size, type, condition, and usage of each ball. There are five sizes three types and many uses for all soccer balls. Lastly, perfect pressure is a subjective measure, so to know what the perfect pressure for a particular player is, you would need to ask them. To finish there really is no perfect pressure for everyone.

Background Research\~What Size of Soccer Ball

What size of ball do you think is best here's what it really is. First different types of experiments need different sizes of ball. Next there are five sizes of soccer balls to pick from. Size 5 is used in professional soccer and smaller sizes are used by younger players. Finally some different sizes are used for different experiment types, size 5 for air pressure experiment, size 1 for dribbling experiment, and size 3 for shooting experiment. To conclude this experiment will be using a size 5 ball

Procedure: Setup

1. Gather materials on material list.
2. Tape a meter stick to the wall with the bottom touching the ground.
3. Place camera at the 40 cm mark with a camera stand.
4. Deflate the ball so its flat.
5. Inflate ball to 1 psi (or other air pressures).
6. Record air pressure.

Procedure: Experiment

1. Hold ball on the top of the meter stick.
2. Have your helper start a slo-mo video .
3. Drop the ball.
4. Stop the video after the ball has rebounded to its maximum height.
5. Watch the video to determine the height of the rebound.
6. Record the quantitative data (height of the rebound).
7. Record the qualitative data ( what it looks like ).
8. Repeat steps 1-7 for all trials.
9. Repeat steps 5-6 ( set up) for all pressures.

To start, every increase in the psi made a higher average bounce. After 7 psi the increases where smaller. The rebound height at 10 psi was almost double what it was at 1 psi. An interesting trend noticed was that 5 psi had all the same rebound heights and for 6 psi, only one trial has a 1cm difference.  These were the two most consistent trials. Secondly, during the experiment one change was made, a flashlight was added to make it easier to read the markings on the tape measure. Before the drop there was a lots of little movements to make sure the ball was at exactly the 1 meter dropping height. Lastly, the research that probably was needed was where the best location to drop the ball is and how it it best to drop the ball.  

The hypothesis was proven true. It is true because the data shows that there was an increase in the average rebound heights the higher the psi got. Because the psi was higher, this means there were more particles in the ball. This made the ball harder against the hard ground and so bounced higher.

If you are setting up your soccer ball to get kicked the hardest inflating it to the highest psi is the best. The applications of this experiment can be used or related to in other sports not just soccer. Some examples of these other sports include basketball where the ball needs to be super bouncy or you can't play that sport. Another application for this topic would be landing rovers on Mars. NASA surrounds the rovers in airbags or huge puffy balloons. These airbags need to be a certain psi to ensure that the the rover bounces a little bit but not way too much. For real world soccer applications, because the rebound height didn't change much after 6 psi it might be better to play or practice soccer at about 6 to 7 psi. This is because the ball will be softer than at 10 psi so it won't hurt your foot as much but you won’t lose much rebound speed.

-   Spin on the ball could have slightly impacted the rebound height but not greatly.          - Camera angle could have slightly impacted the height that was seen.   - The pressure gauge could have been slightly inaccurate but very unlikely.  -  Where the ball landed could have slightly impacted the rebound depending how hard the floor board was.  -  When the pump or pressure gauge was removed a little bit of air could have been let out.                                                                    

A 2024 good guide to soccer ball inflation: Perfect Pump. ASI Soccer Company. (2024, October 17). https://asisoccers.com/soccer-ball-inflation-the-perfect-pump/

Adidas FIFA World Cup 26TM Trionda Pro Ball - white | free shipping with adiClub | Adidas Canada. (n.d.). https://www.adidas.ca/en/fifa-world-cup-26-trionda-pro-ball/JD8021.html

Education.com. (2014\, April 10). Soccer science fair project: Air pressure & distance: Activity. Soccer Science Fair Project: Air Pressure & Distance | Activity | Education.com. https://www.education.com/activity/article/physics-soccer-ball/

Gravity - kids | Britannica kids | homework help. britannica kids. (n.d.). https://kids.britannica.com/kids/article/gravity/400109

Maddrum, C. (2012, September 27). Public domain clip art image: Illustration of a soccer ball. Public Domain Files. http://www.publicdomainfiles.com/show_file.php?id=13488043211860#google_vignette

Migros. (2022, February 23). Supportyoursport Migros Sticker - Supportyoursport Migros - Discover & Share Gifs. Tenor. https://tenor.com/view/supportyoursport-migros-gif-24976295

YouTube.  science buddies how to measure rebound . YouTube. https://www.youtube.com/watch?v=kzJ480muh4U

Undefined. (n.d.). Four Multi Colored Soccer Banners. 123RF. https://www.123rf.com/photo_10592851_four-multi-colored-soccer-banners.html

I would like to thank the following people for helping and assisting me with my project

Dustin my dad for providing suggestions and feedback on my project.

Mrs. Luanu my teacher for letting me move out of the suggested testable questions and supporting me though the whole project.

Mr. Bykovskikh my science fair coordinator for answering the questions i had.