By: Dino V

Dino V — Mon, 05 Oct 2009 01:18:59 +0000

if it gets too hot it can melt the cord
References :

By: david g

david g — Mon, 05 Oct 2009 01:13:59 +0000

I guess as heat expands things, a ball is the same so iot would slow downnnn
References :

By: GARY

GARY — Mon, 05 Oct 2009 00:45:59 +0000

Get hit in the knackers with a cold one………

then your`ll see……..
References :

By: clairelouise

clairelouise — Mon, 05 Oct 2009 00:22:59 +0000

its really important. he needs to know that it wont burn him when he picks it up

:p
References :

By: mark m

mark m — Sun, 04 Oct 2009 23:49:59 +0000

MATERIALS NEEDED:

* tennis balls
* thermometer - should range from 40oF - 120oF
* tape measure - at least 100"
* shoebox
* masking or electrical tape (heavy-duty tape)
* refrigerator or small ice chest (with ice)
* heating pad or sunlight
* chair or step ladder
* sealable plastic bags
* tennis court or other surfaces
* video camera (optional)

STEPS TO FOLLOW:

oneReview the background information for this lesson, especially the information on pressure changes with temperature. You may also want to review the information in the textbook on gas laws . Based on what you’ve learned, do you think a warm tennis ball will bounce higher or lower than a tennis ball at room temperature?

twoUse new balls if possible. If you use old or used tennis balls in this experiment be consistent - use balls opened at the same time; used balls should have the same amount of wear.

threeDetermine the surface you will use. The International Tennis Federation conducts ball bounce tests on concrete. You will want to use a court or other (preferably hard) surface. Since you will drop the ball straight down and take measurements as the ball rebounds straight up, avoid windy areas.

fourTo measure the drop and bounce height use a long tape measure at least 100" long. Someone can hold the tape measure up by carefully standing on a sturdy chair or foot ladder or you can tape it to a fence or backboard.

fivePrepare the tennis balls.

Heat three of the balls. To heat:

1. Balls can be left out in the sun for 2 hours or;
2. Balls can be left out in the sun in a closed box for 1-2 hours or;
3. Balls can be placed near or on a safe heat source - wrapping the tennis balls in a heating pad works well.

Chill three of the balls. To chill:

1. Place the balls in sealable plastic bags to prevent wetness.
2. Place in a refrigerator or in a small ice chest with ice.

Room or outside temperature: Leave 3 balls out at room temperature for 1-2 hours.

sixMeasuring the temperature: there are several options to measure the temperature:

1. Measure the temperature of the surrounding air with a thermometer;
2. Use a thermometer to measure the temperature of the ball directly
3. Determine ball warmth or coldness by touch.

Do not remove the heated or cold balls from their surroundings until you are ready to test them.

sevenPrepare a data sheet. A sample also is provided.

eightStand on a chair or footstool near the tape measure. Hold a ball near the 100" mark of the tape measure. Hold a ball with your fingertips and drop the ball. Let the ball fall straight down - don’t push it. How high does the ball bounce on the rebound? Record the height on your chart. Repeat this procedure for each ball until you have at least 10 data points for each range of ball temperatures.

Optional - You can set a video camera up to record the bounce height. Keep the camera focused in the 52" range on the tape measure. You will probably have to adjust the camera height when you test different ball temperatures.

eightAverage your data for each ball temperature: add the 10 ball heights together and then divide by 10.

Record the range of heights for each ball temperature. Plot the temperatures and heights. Use a different color in the plot for each temperature range

Which bounces higher? Why do you think it bounces higher?

eightVariations: You can try this experiment with different brands of balls, balls meant for different courts, old balls, worn balls. Does your data look different?
References :

By: Mike N

Mike N — Sun, 04 Oct 2009 23:29:59 +0000

According to Boyle’s Law of gasses, the hotter the gas inside the tennis ball, the higher its pressure and therefore the higher the bounce.

I reckon you’d have to be pretty darn good to notice the difference.
References :

By: butchtroll

butchtroll — Sun, 04 Oct 2009 23:20:59 +0000

The rebound of the ball depends upon the compression of the gas inside of it. The hotter it is the more the gas expands and the harder and bouncier the ball gets.
References :

By: tucksie

tucksie — Sun, 04 Oct 2009 22:38:59 +0000

The hotter it gets, the bigger and harder it gets. Makes it faster.
References :

Comments on: what is the importance of the temperature of a tennis ball to a prof tennis player?