Does the size of a basketball affect how high it bounces

Surface Science: Where Does a Basketball Bounce Best?

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Key concepts
Energy
Gravity
Physics
Sports
 
Introduction
Playing basketball can be hard work. Players not only have to run around the court, but just dribbling the basketball takes some serious effort, too. Have you ever wondered why that is? The challenge has to do with how the basketball bounces. When the ball hits the court, its bounce actually loses momentum by transferring some of its energy—into a different form. This means that to keep the ball bouncing to the same height, players must continually put energy into the ball with each bounce. In this activity you will explore how high a basketball bounces on different surfaces compared with the height from which it was dropped. Which surface lets the basketball bounce the highest? Grab a basketball and try this activity to find out!
 
Background
Playing a game of basketball can be great exercise, and one part of that workout comes from just dribbling the ball. Why is this? When a basketball hits the ground (and as it flies through the air), it actually transforms some of its energy to another form. If players do not put enough energy back into the ball, they will not be able to dribble it effectively.
 
When a basketball bounces, it has two different types of energy: kinetic and potential. Kinetic is the energy an object has due to its motion. Potential energy is that which is stored in an object—its potential for motion—such as due to its height above the ground. For example, when you hold a basketball at waist level, it has some potential energy. If you drop the basketball, the force of gravity pulls it down, and as the ball falls its potential energy is converted to kinetic energy. When a basketball hits a court floor, a part of the kinetic energy gets converted into sound or heat, some of it briefly changes the ball’s shape (flattening it slightly) and a portion is absorbed by the floor surface.
 
Materials

• At least two different surfaces to bounce a basketball on, with at least one hard surface and one soft surface (For example, you could use carpet, concrete, grass, linoleum and a basketball court. The surface needs to be flat and next to a wall or other large perpendicular surface.)
• Tape measure or yardstick
• Painter's tape or masking tape
• Basketball
• A helper
• Video camera and access to a computer or a large screen on which to watch your recorded video (optional)

 
Preparation

• Prepare the walls or other vertical surfaces next to the floor types you want to test so that you can estimate the height of the basketball's bounce. To do this use a tape measure or yardstick along with the painter's or masking tape to mark every eight inches, starting from where the wall meets the floor and going up to 40 inches high on the wall. You should end up with five tape marks on each wall.
• If you are using a video camera, ask your volunteer to set it up so that all of the marked wall measurements as well as the floor are in view. When you're ready to test the basketball on a surface, ask your volunteer to start the video camera.
• If you are not using a video camera, ask your volunteer to get ready to watch when you drop the basketball to see roughly how high it bounces after it first hits the ground.

 
Procedure

• Hold the basketball so that the bottom of it is lined up with the top edge of the highest tape mark you made.
• Drop the ball. (Do not push it down.)
• Let the basketball bounce back up and then hit the ground a second time before you catch it in your hands (then stop recording if you were doing so). How high does your volunteer say the basketball bounced after hitting the ground the first time?
• Repeat this, dropping the basketball on the same surface a few more times to give you a good idea of just how high it bounces when being dropped from a certain height.
• Repeat this entire process with the other surface(s) you want to test. How high does the basketball bounce off another surface compared with the first one you tested? Why do you think this is?
• Tip: If you are testing a surface that is at a very different temperature (such as concrete outside on a cold day), you will want to do your testing quickly so that the ball does not change temperature too much. A change in the ball's temperature can also affect how it bounces.
• If you videotaped the basketball bounces, watch your videos to try to more closely estimate the basketball's bounce height on the different surfaces.
• Extra: Try to quantify your results from this activity. To do this, you'll want to videotape your bounce trials and closely watch the videos on a large screen to determine the exact height of the basketball before it was dropped and the highest point of its first bounce. You could even graph your results. Exactly how high does the basketball bounce on each of the different surfaces?
• Extra: A basketball loses kinetic energy by transferring it into other forms when the ball bounces. But just how many bounces can a basketball make before losing all of its kinetic energy and stopping bouncing? And how does this change if you alter some factors, such as the type of surface the basketball bounces on or the drop height? Design an experiment to investigate how many bounces a basketball can make and how various factors affect that number, and then try it out!

 
Observations and results
Did the basketball bounce much higher on the harder surface compared with the softer one?
 
One factor that can affect the basketball's collision with the ground is the type of surface the ball collides with. When a basketball bounces off of a surface, some of its energy is absorbed by that surface. Some surfaces absorb more energy than others do. (How much energy gets absorbed determines how much energy a player has to put back into the ball to keep it bouncing.) A hard surface, such as concrete, absorbs less energy compared with a soft surface, such as a carpeted floor. The more energy absorbed by the surface, the less that remains in the ball for it to bounce. This is why you should have seen that when you bounced the basketball on a relatively hard surface it bounced higher (it lost less energy) compared with when it was bounced on a softer surface (where it lost more energy). For example, depending on the type of basketball and surface, you may have seen the ball bounce about 15 inches high on carpet and about 25 inches high on concrete.
 
More to explore
Physics of Dribbling a Basketball, from Physics
Elastic and Inelastic Collisions, from HyperPhysics, Georgia State University
Fun, Science Activities for You and Your Family, from Science Buddies
Bouncing Basketballs: How Much Energy Does Dribbling Take?, from Science Buddies

This activity brought to you in partnership with Science Buddies

ABOUT THE AUTHOR(S)

Bouncing Ball Physics: What is Elasticity? | Science project

Science project

What makes a ball bouncy? Have you ever wondered why some balls bounce higher than others? A ball’s ability to bounce has a lot to do with its elasticity. So what is elasticity? It’s an object’s ability to return to its original shape after being stretched or squeezed. Objects that are more stretchy are usually more elastic, too. Do you have pajama pants with elastic material in the top? You can stretch to get into them, but they will shrink back to fit your waist!

In this science fair project, we’ll investigate bouncing ball physics to determine which ball has the highest elasticity and find out how elasticity contributes to bounce height.

Download Project

Grade

Third Grade

Which of the following balls has the highest elasticity: a rubber ball, a marble, or a ping pong ball?

• Wooden board (a cutting board or a piece of scrap plywood will work great)
• Yardstick, meter stick or tape measure with centimeters
• Rubber bouncy ball
• Marble
• Ping pong ball
• Table or wall
• Tape

1. Set the wooden board flat on the ground next to a wall or table.
2. Tape the meter stick to the wall or table as shown. Make sure that the meter stick starts with 0 is at the bottom. Before conducting this experiment, use this time to formulate your hypothesis. Which ball do you think will bounce the highest? Why?

3. Have a partner drop the rubber ball from the 25 centimeter mark and record the height of the first bounce in a table like the one below. Repeat 5 times and record bounce height for each of your 5 trials. It’s important to drop the ball and not throw it downward. Why do you think this is?

4. Average the recorded bounce heights from each trial together to find the average bounce height for the rubber ball. Here’s how to calculate an average:

5. Repeat steps 3 and 4 for the marble.
6. Repeat steps 3 and 4 for the ping pong ball
7. Have a partner drop the rubber ball 5 times from the 50 centimeter mark and record the height in a table.
8. Average the recorded bounce heights from each 50 cm trial together to find the average bounce height for the rubber ball.
9. Repeat steps 7 and 8 for the marble.
10. Repeat steps 7 and 8 for the ping pong ball.
11. Have a partner drop the rubber ball 5 times from the 75 centimeter mark and record the height in a table.
12. Average the recorded bounce heights from each 75 cm trial together to find the average bounce height for the rubber ball. How do you think the height at which the ball was dropped affects how high it bounces? Why? You should see a pattern emerging!
13. Repeat steps 11 and 12 for the marble.
14. Repeat steps 11 and 12 for the ping pong ball.

On average, the rubber bouncy ball will bounce the highest, followed by the ping pong ball. The marble will bounce the least high.

When all three balls are dropped from the same height, the rubber ball will bounce the highest because it has the greatest elasticity. When the rubber ball hits the ground it gets compressed, or squished, and because it is very elastic, it quickly returns to its original shape. When it does this, it pushes back on the ground shoots back up into the air.

The marble, which is the hardest out of the three balls, has the least elasticity, so it does not bounce as high. It doesn’t get squished when it lands, so it has a harder time changing its direction from down to up. The balls dropped from 75 centimeters will bounce higher than those dropped from 50 centimeters, and the balls in the 50 centimeter trials will bounce higher than those in the 25 centimeter trials. This is because the higher the starting height of the ball, the higher the ball’s potential energy. An object has potential energy because of its position. If an object is going to be dropped from high up in the air, it has lots of potential energy because the earth’s gravity has plenty of time to accelerate, or speed up, the ball when you let go of it—and the longer an object falls, the faster it gets. So what happens to potential energy when a ball is dropped? It turns into kinetic energy, or the energy an object has when it is moving. The faster an object moves, the higher its kinetic energy. Which object do you think has a higher kinetic energy: a car or an airplane?

Because gravity has the most time to do its job when the balls are dropped from 75 centimeters, these balls have the most kinetic energy by the time they hit the ground. When the ball hits the ground, all that kinetic energy has to go somewhere. A lot of it goes back into the ball, giving it more force to pop back up into the air—so the higher the potential energy, the higher the kinetic energy, and the higher the kinetic energy, the higher the bounce!

To explore gravity and gravitational forces, get a stopwatch and time each ball from the time it is dropped until it hits the ground. Which ball hits first? Does weight matter? Does elasticity matter?

Result: All balls should take the same amount of time to reach the ground when dropped from the same height. Weight and elasticity do not matter.

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Influence of air pressure on ball bounce height

• Authors
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• Job files
• Award documents

Chernyshev G.S. 1

1GBOU School 2120

Vagidova Z.R. 1

1GBOU School 2120

The author of the work was awarded a diploma of the winner of the III degree

Diploma of a student Certificate of the head

The text of the work is placed without images and formulas.
The full version of the work is available in the "Files of the work" tab in PDF format

Introduction

The ball is one of the most favorite toys for boys of all ages. There are many ball games such as football, volleyball, basketball, golf. Each game has its own ball. We know that there is air inside any ball. Therefore, the question arises: why don't all balls bounce?

Relevance: the ball is one of the most important attributes of games. Knowing the properties and types of balls helps in choosing them. Each person should have an idea about the physical phenomena and laws that he directly encounters in everyday life from childhood.

The purpose of is to study the effect of ball pressure on the height of the jump on the height of the first bounce.

Item is a basketball.

Item - air pressure in the ball.

To achieve this goal, it was necessary to solve a number of tasks:

1. Collect literature on the topic;

2. select research methods;

3. study the history of the origin of the ball, its varieties;
4. find out what sports games are played with the ball;
5. conduct an experiment explaining why the ball jumps to different heights after the amount of air in it changes;

6. draw conclusions.

Thanks to the following methods , a study was performed:

- work with Internet sources;

- work with literature;

- analysis;

- comparison.

Starting the study, we put forward the following assumption : if you release air from the ball, it will bounce lower.

Problem question of our study is: How does the amount of air in a basketball affect how high it bounces? How do basketball players determine how much air a basketball needs to have in order to play?

The novelty and practical significance of our study as a whole lies in the choice of the ball as the object of study.

1. Theoretical part.

1.1. Communication with history and science

In the encyclopedia "I know the world" it is said that the ball is one of the most ancient and favorite toys of all countries and peoples. In ancient Greece, it was considered the most perfect object, since it had the shape of the sun, which means (as the Greeks thought) it had its magical power. They sewed balls from leather and stuffed them with some elastic material, for example, moss or bird feathers. And later they guessed to inflate the leather ball with air. Such a ball was called "follis". Small follices were used for hand games, and large balls were used for games like football. Images of balls were found on the walls of Egyptian tombs, and during excavations of the burial places of the pharaohs, balls themselves were found, sewn from strips of leather or tree bark, and sometimes made of sandstone. The team games of the Egyptians with these items were dedicated to the gods, each team represented the interests of a group of celestials, the ball was driven into the gate with curved sticks. [1
And in ancient China they played ball, for example, by kicking it with their foot. The game eventually became a favorite folk entertainment, and in the 2nd century BC. included in the obligatory program of the solemn celebration of the birthdays of the emperor. At the same time, instead of stuffing with bird feathers and animal hair, they learned to fill leather balls with air, developed rules, and began to install gates on the playing field. The winners were honored with flowers, awarded with valuable gifts, and the losers were beaten with bamboo sticks.
In ancient Japan, too, they could not do without a ball. At the imperial court, team games were held to drive the ball into the goal for a certain time (measured by the hourglass), during the throw it should not touch the ground.
In Russia, the balls were different. In excavations near Novgorod, balls of various sizes were found, sewn from leather. They were played by children in the 13th century. Peasant children played with light balls made of birch bark or heavy balls tightly rolled from rags. Even information about one of the games has been preserved: they put chicken eggs in a row and knocked them out with a ball. In the Khotkovsky nunnery near Moscow, balls were sewn from soft pillows, and pebbles wrapped in birch bark were put inside - it turned out to be a ball and a rattle at the same time. By the way, the origin of the word "ball" is associated with the words "soft, pulp, crumb." That is, the ball is a soft ball.

Modern balls vary in size and purpose. Different balls are used for playing volleyball, basketball, football, tennis, water polo, rugby and other games.

Each of them has its own story. The name of the game of basketball came from the English words "basket" - "basket" and "ball" - "ball". This game was invented by D. Naismith, a sports instructor from one of the American universities, in 1891. At his direction, a large fruit basket was nailed under the ceiling of the sports hall and a ball was thrown into it. When the players got tired of climbing for the ball every time, it occurred to someone to just knock the bottom of the basket out. At first, basketball players used leather balls, and then switched to rubber ones.

The basketball must be spherical and must be the specified shade of orange with the traditional pattern of eight inlays and black stitching. The mass of the ball (officially accepted size 7) is 567-650 g, the circumference is 750-780 mm. Smaller balls are also used: in men's team games, "size 7" balls are used, in women's team games - "size 6", in mini-basketball matches - "size 5".

1.2. Definition of concepts

Working with the dictionary of S.I. Ozhegov, we learned that a ball is an object for playing a solid or full ball made of an elastic material inside, which bounces off a hard surface upon impact. [2]

Pressure is a physical quantity equal to the ratio of the force acting perpendicular to the surface to the area of ​​this surface.

Unit of pressure - Pascal (Pa). Using also other pressure units: hectopascal (hPa) and kilopascal (kPa) 1 kPa = 1000 Pa 1 Pa = 0.001 kPa 1 hPa = Pa 1 Pa = 0.01 hPa

The force arising in the body as a result of its compression and stretching (deformation) tending to return the body to its original position is called the elastic force.

According to the free encyclopedia "Wikipedia" elasticity is the property of solid materials to return to their original shape during elastic deformation. Solid objects will deform after a force is applied to them. [3]

Basketball size

First of all, when choosing a ball, you should pay attention to the size of the basketball. Size 7 means you are holding a ball that is suitable for men. Its weight can range from 567 to 650 grams. Size 6 is primarily used in the games of teenagers under 16 and adult women's teams. In addition to the circumference, its weight has also been reduced - from 510 to 567 grams. Size 5 is officially suitable for training and games of junior teams, with a weight of 470-500 grams. Of course, in your training you can use the size of the ball that you have at hand. By learning to handle a size 7, you are more likely to master a size 6 with ease. Unfortunately, the inverse doesn't always work.

2. Practical

In the practical part, we had to solve the following tasks:

- determine how the height to which the basketball bounces changes when the air pressure changes in it;

- build a graph based on the received data;

- draw conclusions based on the data obtained.

Different manufacturers measure pressure in different units, psi (pounds per square inch), bar (pressure unit approximately equal to one atmosphere), kgf/cm² (one kilogram of force per square centimeter), kPa (kilopascal). In the United States of America, the pressure inside the ball is usually measured in pounds per square inch (lb/dm ² ).

We experimented with the amount of air in a basketball, but for measurement, we used units that are accepted in our country, namely kilopascals (kPa).

We measured the amount of air in a basketball and then used a distance sensor to measure how high the ball bounced.

Materials and equipment:

- Computer with the Logger Lite program installed on it;

-Go!Link adapter;

- Gas pressure sensor;

- distance sensor;

- Basketball;

- Stopper with needle, stem and tube;

-Measuring ruler.

Our experiment was carried out according to the following algorithm:

To configure the sensors for data collection, you need:

Check distance sensor connection to computer.

Set the distance sensor switch to position Normal .

Make sure the pressure sensor is connected to the adapter and the adapter is connected to the computer.

Start the Logger Lite program.

Open file for this experiment Air Ball (Air ball) .

Then did the following:

They took a basketball.

Reset the pressure sensor by pressing the Reset button on the toolbar. Next, the sensor measured the pressure in the same way as the measuring device on a bicycle pump.

Moistened the needle attached to the pressure transducer and inserted it into the ball.

Recorded data in the first line of the column "Actual pressure" of the data table.

Attached the distance sensor at a height of 2.3 m.

To collect data, did the following:

Hold the ball directly under the sensor so that the space between the ball and the sensor is about 15 cm.

Button pressed Data acquisition . Hearing the click of the sensor, they released the ball from their hands so that it hit the floor and bounced. No need to throw the ball with force!

Next, press the button View, to determine the position of the floor relative to the sensor and the distance to the ball at the top of the rebound ball #1. We recorded the obtained data in a table.

Next, we gradually reduced the pressure in the ball:

Moistened the needle attached to the pressure transducer and inserted it into the ball.

Watched the pressure reading on the screen.

Released some air.

Watch the pressure reading on the screen until it drops by 20 kPa (for the first time, the pressure will drop from 124.88 kPa to 105.79 kPa).

When the pressure dropped by 20 kPa, twist the connection tip so that no more air escapes.

Recorded the value in the second line of the "Actual pressure" column of the data table.

Repeat steps 3-7 for 80 kPa, 60 kPa, etc. until you reach a test where the pressure was 5 kPa.

Data table (graphs are in the appendix):

Drop height 2.321 - ball distance 0.214 m = 2.107

Pins:

There is a pattern of change in the height of the rebounds with a decrease in pressure in the ball - the height of the rebounds decreases. The lowest air pressure in the ball allowed for playing basketball: 80 kPa.

Conclusion

What is basketball training without the main attribute of the game - a basketball? It is the basketball that gives us the opportunity to enjoy the gameplay in all its diversity.

Often when inflating a basketball, the question arises whether to inflate it more or less. We have to resort to the help of the Internet in search of information regarding this issue. We decided to answer the question, what is the optimal pressure should be in a basketball, since with the wrong level of pressure, the wear resistance of the chamber increases, which may simply not withstand and burst; there is a risk of injury; unpredictable flight path. The lowest air pressure in the ball allowed for playing basketball: 80 kPa.

Our study was carried out using Logger Lite software, Go!Link adapter, gas pressure sensor, distance sensor.

To achieve the goal, tasks were set that were successfully solved. To begin with, the literature on this topic was collected. Its analysis is presented in the theoretical part.

Getting to the practical part, we have identified research methods. Thanks to them, our study "The effect of air pressure on the height of the ball rebound" was carried out.

The hypothesis that we put forward at the beginning of the work was confirmed.

Having completed this study, we have developed a memo for fans of the game of basketball ( Appendix 2 ).

References:

I know the world. Sports: children. encyclopedia. - M.: AST: Astrel: Transitbook, 2006 - 382.

Ozhegov S.I. Explanatory Dictionary of the Russian Language, M .: LLC "A TEMP", 2008. p. 810

[Electronic resource] Access mode: Wikipedia - Head. from screen

[Electronic resource] Access mode: https://sportyfi.ru/basketbol/myach/kak-nakachat/ Head. from screen

Appendix 1

Experiment 1

Height

Pressure

Experiment 2

Height

Pressure

Experiment 3

Height

Pressure

Experiment 4

Height

Pressure

Experiment 5

Height

Pressure

Experiment 6

Height

Pressure

Experiment 7

Height

Pressure

Experiment 8

Height

Pressure

Annex 2

Instruction for inflating a basketball

Note:

The pressure in the ball is quite strongly influenced by the ambient temperature and atmospheric pressure.

It is better to inflate the ball directly where games or training are planned.

The ball must be inflated correctly! Before pumping, you need to shake the ball so that the chamber is in a vertical position, below the valve opening. Then pump it up.

Job views: 513

How to choose a basketball?

Basketball is a fast and dynamic sport. To enjoy the gameplay, you need to buy high-quality inventory. Basketball equipment is presented in a wide range. Many well-known brands are engaged in the manufacture of balls for this sport. Which option to choose? Consider the main criteria.

Types of basketballs

One of the most important selection criteria is the purpose of the ball. With this, you need to start looking for a suitable projectile, we will start with this, in total there are three types:

• for the hall;
• for the street;
• universal.

The Indoor Basketball has excellent grip on parquet. Made from nat. leather or synthetics. Professional athletes choose models with a composite coating. Microfiber provides a comfortable grip. The material muffles impacts during the dribble. It is forbidden to play on asphalt sites, as in such conditions the projectile will very quickly lose all its qualities.

For the open field (outdoor) use shells made of synthetic raw materials. This composition makes them extremely resistant to wear. Additional surface treatment enhances grip. The ball is easy to control.

Universal shells are made of rubber. It is resistant to wear, behaves normally on parquet and can serve for quite a long time on open street areas. Some are covered with synthetic or composite materials. Manufacturers produce goods for sites with a smooth, wooden, rubber coating.

How to decide on the material

To understand how to choose a basketball, take into account the raw materials used in production. Durable versatile basketballs are made from artificial materials. Many professional indoor balls are made from composite leather.

Genuine leather is considered the best material for the hall. The leather ball is an essential element of any professional basketball tournament. If you see the marking “Supreme Leather” on such a ball, then the manufacturer used premium leather.

Quality check

The first evaluation method is rebound. A correctly inflated ball will bounce to a height of approximately 130 centimeters. There is an alternative way. Raise the professional ball to head level, and then release it. He should bounce to the waist. Look at the quality of the nipple.

Do not sit on it or kick it to keep its original shape. Careful use preserves the correct rebound during the dribble. Elasticity is another indicator of quality. The ball must not become soft after a short play. Pump up periodically, but use only a special nozzle, and not a football needle.

Size

What size basketball should I buy? It all depends on the specifics of use. Marking No. 7 - the largest ball is intended for competitions of men's teams. The table shows absolutely all existing sizes:

Size