EPS 200                                                                                              Name: _______________________

Pressure/Buoyancy/Temperature

Hot Air Balloon Project

Overview: 

• Design and construct a hot air balloon that will lift the most weight with the provided materials and minimal use of the shrink wrap sealer.  [Laser cut or 3-D printed trophy for the winners.  Top 3 groups get extra credit.]
• Create a scale model and use it to predict the mass and volume of your final balloon.
• Predict the temperature to which the air in your balloon must be raised in order to float in room air. 
• Calculate the temperature actually reached by the air inside your balloon.

Rules/Requirements:

• Max group size = 2 students*.
• The balloon hole (above your flame) must be at least as large as an 8” diameter circle. [A 8” diameter circle must fit inside your balloon’s hole.  If it does not, you will not be allowed to fly your balloon.]
• Your balloon envelope (big balloon part) may consist of no more than one of the provided plastic sheets (approximately 6’x9’)
• Your balloon’s power source must consist of only the fuel provided by Mr. Stapleton

Contest Scoring: ***does not determine your grade*** Highest score wins.  Score will be based on...

• grams of mass lifted [1g = 1 point]

• accuracy of prediction/planning (scale model vs actual balloon) [point calculation = -(% error) /5]

• simplicity (length of required cutting/sealing) [point calculation = - (length of sealed edges, in meters)

Provided Materials:

• One rectangle of 0.5mil plastic sheet (approximately 6’x 9’)
• Fuel (alcohol – 10g of Sterno®)
• Thin wire
• Aluminum flashing (to create a platform for fuel)

Provided Tools:

• Sealer/cutter (originally used for shrink wrap)
• Scissors
• Pens
• Scotch tape
• Meter sticks
• Planning grid for designing your balloon

Completion Phases:

1. Create a scale model balloon envelope out of paper and scotch tape
   • Use your model to predict your final balloon envelope mass and volume.

   • Create a model of your balloon's basket and basket support material

2. Calculate the density of your balloon (with predicted characteristics) at an air temperature of 200 degrees Fahrenheit.  Compare this to the density of air.

3. Consider your design and redesign if necessary.  Remember that you are trying to maximize lift, minimize seam lengths, and make accurate predictions.

4. Build your balloon.

5. Measure your balloon's empty mass and filled volume.

6. Fly your balloon and measure its lift.

7. Calculate your balloon's buoyant force, interior air mass, and interior air temperature