4-H VOLUNTEER INFORMATION SERIESN e b r a s k a 4 - H Y o u t h D e v e l o p m e n t

It’s Just Rocket Science: Calculating Rocket Launch Height

Outcome Area: X SET __ Healthy Lifestyles __ Life Skills __ Career Development

Curriculum Area: Aerospace

Specific Project (s): Aerospace 2, Aerospace 3, or Aerospace 4

Description of Activity: This activity will help youth determine more precisely how high their rockets go when they are launched.

Age Level: 8 - 18

Group Size: Any size

Time Involved: Preparation time: 10 min Activity time: 60 min.

Materials Needed: Altimeter Construction:

Protractor or Paper Protractor from Packet (If using the paper protractor, youth will need to glue the paper protractor to cardboard for added strength.)

Masking tape String Heavy Washer Straw Altitude Calculations: Sample Rocket Launch Data Rockets Away Manual Calculators (Optional) Objectives: Youth will understand how science and technology relates to their 4-H projects. Youth will develop positive attitudes about science and technology.

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Activity: Anticipatory Set:

Leader will ask youth to discuss how to determine how high their rockets fly when they launch them. They may suggest that they can tell how high they fly by knowing how high other items are in the area. If they do you can ask them how they know how high those objects are. If not, let them determine their best theory for determining the height of their rocket launches. Leader should explain that we can use measurements to determine more scientifically how high our rockets fly. One method for doing this is to use an altimeter to determine the angle for the highest point of the rocket launch. Leader should use the enclosed diagram of a rocket launch to explain how the altimeter can be used to determine rocket height. Using the diagram, demonstrate how a protractor can be laid on top of the diagram to determine the angle of the rocket launch. From the angle, show students how to use the Table of Tangents found on page 23 of your Rockets Away manual to determine the tangent of that angle. The tangent can be multiplied times the distance between the rocket launch pad and the observation location to determine the exact height of the rocket launch.

Building an Altimeter: You may either choose to use actual protractors or a paper copy of a protractor. If you are using a paper copy, you will need to cut out the protractor and glue it to cardboard for additional durability. First tie a heavy washer to some string using a double knot. Once you have the washer secured to one end of the string, cut the string a couple inches longer than the radius of your protractor. Using the string that has been secured to the washer, tie the opposite end of the string to the center of the flat edge of the protractor. If you are using the paper version, you can simply tape the string to the protractor. Make sure that it’s exactly in the center. If the string has been secured in the center of the protractor, you will be able to swing the washer around the curved edge of the protractor and it will remain evenly spaced around the curve. Next cut a straw to be the same length as the flat edge of your protractor. Secure the straw to the flat edge of the protractor, making sure that it remains perfectly parallel with the flat edge. Your altimeter is now complete.

How to Use Your Altimeter: Altimeters should be held at a right angle to the ground, with the flat edge toward the top. If you’re having problems envisioning this, tell youth to hold it in their left hand like a trumpet. The rounded edge should be toward the ground. The string and washer apparatus should swing freely along the curved edge of the altimeter. When you have launched your rocket, you will want to hold the altimeter in your left hand and use the straw to align the flat edge of the altimeter with

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the peak of the rocket height. The rocket goes fast, so you may have to practice first on a stationary object, such as a telephone pole, tall building, or grain elevator. Holding it steady at the peak, bring up your right hand and hold the string against the altimeter. Then you can level the altimeter like a table top to make the final reading. HINT: When you are first practicing using your altimeter, you may find it helpful to have two or more youth measure the angle of the same object and compare notes. It also is helpful to have

students round their angle to the nearest 5°.

Calculating the height of your rocket launch:

It is always good to do a few practice runs with the calculations before you actually launch, however, if you choose to you can also launch your rockets and then do the calculations on the actual data. Using the Sample Rocket Launch Data, and the Table of Tangents Chart on page 23 of your Rockets Away manual, determine the tangent for each of the launch angles on the sample data. Next have students multiple the tangent of the angle with the distance from the rocket to determine the actual height for each sample rocket launch. Sample Rocket Launch Data

Launch Angle Tangent Baseline Height

Sample #1 45° 100 feet

Sample #2 30° 200 feet

Sample #3 35° 250 feet

Sample #4 25° 250 feet

ANSWERS: Sample Rocket Launch Data

Launch Angle Tangent Baseline Height

Sample #1 45° 1.00 100 feet 100 feet

Sample #2 30° .58 200 feet 116 feet

Sample #3 35° .70 250 feet 175 feet

Sample #4 25° .47 250 feet 117.5 feet

Closure:

Remind students that by applying scientific measurements to their rocket launches that they can be more precise at estimating the actual height of each rocket launch. Additional Learning Opportunities:

1. Have youth launch their rockets and use two or more altimeter measurements to more precisely determine actual height of rocket launches.

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2. Apply knowledge of altimeter use to new subjects, such as how high Chimney Rock is if you are standing in Gering. (HINT: Gering is approximately 18 miles from Chimney Rock).

3. Assuming that a youth launches a rocket three times on the same day, what factors may account for differences in the height achieved by each launch.

References:

Horton, R. L., Newman, B., Dandareau, C. (2006). Rockets away! A fun approach to exploring the science of rocketry. Ohio State University Extension.

Glenn Learning Technologies Project (2004). Altitude Tracking. Available online: http://www.grc.nasa.gov/WWW/K-12/TRC/Rockets/altitude_tracking.html#navskip

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