Hovercraft Test Pilots

Here are some plans for building two hovercraft test models. Your first goal is to compare the models to see if the weight of the hovercraft affects how it hovers. But weight may no be the only thing that affects hovering. Your mission is to discover what other factors are important. You can design more test models with materials you find at home or at school. Just remember to change only one part at a time on each new models so that you can tell which changes make the hovercraft work best. Keep track of your findings in a chart. At the completion of your mission, you will challenge your partner to a hover race with your very best designs. Good luck and happy hovering!

• 2 paper plates or Styrofoam trays (same shape and size)
• 2 toilet paper or paper towel tubes (or make tubes from cardboard)
• 1 brown paper grocery bag (or sheet of stiff paper or posterboard)
• 1 thin plastic trash bag (or frozen food bag)
• masking tape
• metric ruler
• pencil
• scissors
• smooth, flat table, counter top, or uncarpeted floor
• blow dryer (optional)

You may want different sizes or shapes of plates and trays, plastic margarine tubs, aluminum pie plates, longer or shorter tubes, foil, wax paper, or other such items.

1. Stand a paper tube in the center of each paper plate or tray. Trace around it with a pencil. Carefully cut out the circles.
2. Turn the plates upside down and gently push one end of a paper tube in the openings. Make sure the tubes fit snugly.
3. Make a "heavy skirt" for one plate by cutting a 5-cm strip of grocery bag and taping it around the sides of a plate. Make a "light skirt" for the second plate by cutting a 5-cm strip of plastic bag and taping it around the sides.
4. Set the plates on a smooth, flat table or floor. Adjust the tubes so that their bottoms don't touch the table. Blow two or three times into each tube and see what happens.
5. Compare how each plate moves. How does the weight of the skirt affect how the hovercraft hovers? Write down the test results that you observed.
6. If you have a blow dryer, you can compare blowing air from you lungs to blowing air from the dryer down the tube of one of the models. How does the amount of air affect hovering? Write the results you observe for test 2 in the chart.
7. What would happen if you changed the shape of a model? How about comparing long and short tubes? Think of improvements you can make and then change one of the models so you can test if it improves hovering. There are lots of changes you can make. Just remember to compare only one change at a time! Keep track of your changes and test results in the chart.
8. Challenge your partner to a hover race with your very best test models. Which pilot hovers the model to the far side of a table the fastest? Think about the race results. What other improvements can you test on your model?
9. Look at your test results chart. What did you find out about hovercraft? List four things you found that make a big difference in how hovercrafts hover.