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### Course: Middle school physics - NGSS>Unit 5

Lesson 2: Unit 3 activities

# Activity: Why doesn't a basketball bounce forever?

Make science come alive in your classroom with this free hands-on activity aligned to middle school NGSS standards.

## Activity: Why doesn't a basketball bounce forever?

If you drop a basketball and don’t dribble it, what would you hear over the next few seconds? Boing…….. boing…... boing…. boing.. boing. Then silence.
The familiar pattern of a ball bouncing to smaller and smaller heights before coming to rest is not unique to basketballs. Tennis balls, golf balls, and many other objects behave in a similar way when dropped.
Why don’t basketballs and other “bouncy” balls bounce forever? In this activity, students will use rubber balls and their knowledge of energy to develop an explanation.

### Overview

This activity is designed to be completed in two 45-minute class periods, with additional time required for follow-up creative projects. The activity consists of the following parts:
• Setting the stage—Students review the fundamentals of energy transformations, transfers, and conservation. (15 minutes)
• Investigation (Part 1)—Groups record the height reached by a bouncing ball after successive bounces. Students graph and analyze their data, using their results to answer questions about the system and sketch a model. (20 minutes)
• Investigation (Part 2)—Students use their graphs to predict how high the ball will travel after an additional bounce. Groups then record data for an additional bounce to test their predictions. (10 minutes)
• Let's get creative!—Students apply their knowledge to create a presentation for a kids basketball camp. In it, they explain the energy changes which take place as a basketball bounces, and why dribbling the ball is necessary to keep it bouncing. (45 minutes)
• Keep creating!—Students can choose from additional project ideas. Each project encourages students to combine scientific knowledge with creativity to produce something new.

### Download the worksheets and get started today!

You can print out this activity or upload it to a digital classroom.

### NGSS performance expectations

MS-PS3-2. Develop a model to describe that when the arrangement of objects interacting at a distance changes, different amounts of potential energy are stored in the system.
MS-PS3-5. Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object.

### Give us feedback!

Have you tried this activity? Tell us your thoughts in this short survey.

## Want to join the conversation?

• I have a theory... that I doubt is true but it makes sense. See, let's say when you were 3, you decided to drop a bouncy ball on the parking lot from a 5 story building. So, we know that as it bounces, the energy is slowly seeped into the ground until the ball has none. So, the energy has been transferred to the ground and according to the laws of physics energy is never created nor destroyed so is that energy from the ball, 10 years later, TECHNICALLY still in Earth roaming around and doing whatever energy does? Just curious ^^
(28 votes)
• More specifically...

Your theory is not far off from the truth! According to the Law of Conservation of Energy, energy cannot be created nor destroyed; it can only be transferred or converted from one form to another. So, when you dropped the bouncy ball from the 5-story building, the ball's kinetic energy was transferred to the ground upon impact, causing a small vibration in the ground. The vibration then dissipates into heat energy and sound energy as the ground returns to its original state. While the energy itself is not necessarily "roaming around," it has been absorbed by the surrounding environment and converted into different forms of energy, such as heat and sound. In other words, the energy that was once in the bouncy ball is now spread out among various forms in the environment.
(31 votes)
• Can something bounce without making a noice?
(9 votes)
• Yes, something can bounce without making a sound. For example, if you drop a ball on a soft surface like a pillow or a foam mat, it will bounce without making much noise. However, if you drop the same ball on a hard surface like concrete or wood, it will make a sound when it bounces1.

I hope this helps!
(9 votes)
• to sum it up in a nutshell the basketball does not 100% elasticity
(3 votes)
• While basketballs can bounce for a while on their own, they're slowly loosing their kinetic energy and just stop moving until force is applied to it again.
(1 vote)
• Why do a tennis ball bounce, but not a tennis racket?
(2 votes)
• A tennis racket will slightly bounce [Like when it does a little thud and comes back up then rests] but it doesn't bounce as much as the tennis ball due to what it's made of, tennis balls are also hollow on the inside, making it weigh less.
(1 vote)
• why do certain balls bounce higher than others.
(0 votes)
• The bounciness (??) of a ball is determined by the elastic qualities of the materials it is made up of. For instance, let's compare a basketball with a bowling ball. The basketball is going to bounce much higher than the bowling ball because it is made of rubber and filled with air. As the ball hits the ground, the sides get compressed. This compression stores a certain amount of potential energy in the basketball. The sides push back out, which causes the ball to bounce back up. Because the rubber is elastic (can be shaped then reformed) and the air is compressible, the basketball bounces. Now, the bowling ball is made up of some not-so-elastic material. Also, the bowling ball is solid, unlike the basketball, which is filled with air. So, when determining bounciness, we look for which materials are the most elastic and which insides are the most compressable.
I hope this helps!
FreeRadical
(9 votes)
• The energy decreases as the ball bounces, but energy won't just disappear right? Where does the energy go?
(1 vote)
• In this case, the energy that's lost is due to heat, from the collisions of the ball with air particles, but mostly when the ball collides with the ground. This loss of energy due to heat is also why the ball doesn't quite reach the same height after each bounce, because after a bounce, the ball has lost some energy. Notice, I haven't mentioned gravity or forces at all. Gravity essentially just keeps pulling the ball down.
(2 votes)
• is it posible for a ball to bounce forever on its own
(1 vote)
• No- the ball, no matter how bouncy it is and what the ground below it is like, will always stop bouncing one day.
(3 votes)
• When a basketball bounces (without being pushed down), it does not go all the way back up to its original height, as shown in Figure 2 below. This is because the basketball had an inelastic collision with the ground. After a few bounces, it stops bouncing completely. The energy has left the ball!
(0 votes)
• No, the energy has not left the ball, instead has been transferred to the surface it has dropped upon.
(2 votes)
• how does a ball falling changes it's energy
(1 vote)
• Gravity is pulling the ball faster and faster towards the Earth, so the ball is gaining energy.
(1 vote)
• i wonder why everything comes from gravity?
(1 vote)