Video Supplements: Air
Balloon Design Challenge

Overview
Students design and make a hot air balloon using a plastic bag. They measure the time it stays in the air and its distance from the launch point.

Outcome
Students will understand how to convert time and distance measurements.

Standards Addressed — Mathematics

Grade 5
Use Measurement Techniques and Tools, Benchmark B
05. Make conversions within the same measurement system while performing computations.

 

Materials

• A variety of plastic bags — dry-cleaning bags work best
• Two or three hair dryers
• String
• Scotch tape
• Paper clips
• Tape measures
• Clock with second hand
• Balloon Design Challenge student handout

Procedure

1. Divide the students into groups of two or three.

2. Have available various types of plastic bags, string and paper clips. Following are some guidelines:

   Dry-cleaning bags work the best because they are the lightest, but all types should work

   Students can use paper clips around the bottom to keep some balance

   Students should use string to tie off the top if they are using a dry-cleaning bag

3. Have one or two people hold the bag while the other teammate blows hot air into the bottom using the hair dryer. The students should hold the bag until they feel a tug on the material. It is helpful to gather the bottom of the balloon so that the hot air remains in the balloon.

4. Students should measure in seconds (and convert to minutes) the time from when they release the balloon until any part of it touches the ground. Students should further measure the distance from the launch site to the landing site in centimeters (and convert to meters).

5. It is a good idea to do this activity outside (if electricity is available). Sometimes the balloons will go as high as the second story of a school. Indoors, the balloons can generally hit the ceiling.

6. Extension: Older students can use a clinometer to determine the actual height that the balloon met. For instructions on making a clinometer, go to the School Yard Clinometer Web site at www.state.nj.us/dep/seeds/syhart/clinom.htm. The string on the clinometer will show the tangent angle: Tan = Opposite/Adjacent.

7. Science Connection: “When air or any other gas gets hot and expands, it gets less dense (lighter) because the same amount of air occupies a larger space. Hot air balloons fly because they contain warmer, lighter air. The air in the balloon, being warm, is less dense (lighter) than the cool air around it so it floats upward, like a cork in water. When the air gets cool, the balloon will sink again.” (Source: NASA)

Evaluation