Wednesday, August 17, 2011

How to Make a Solar Balloon

Solar balloon technology uses the heat of the sun to help a simply constructed air-inflated structure gain the buoyancy to fly. As the air inside the balloon is warmed by the sun's radiation it expands, and because the air inside has a lower density than the surrounding air, it helps the balloon rise and stay afloat. Using a lightweight dark material to help absorb heat, solar balloons are a great introduction to the concept of how the power of the sun can be utilized.

1) Use scissors to cut the sealed seams off each of the trash bags.

2) Tape the ends of each bag together to form a long tube structure. Ensure that you overlap the edges of each bag by ½ an inch before taping.

3) Seal the bag at the top of the tube with tape and then turn the structure inside out, like you would do with a sock.

4) Taper the open end of the tube with tape leaving a hole of approximately 5 inches in diameter. Add a loop of tape to hang below the mouth of the tube before reinforcing with another layer of tape around the mouth of the tube.

5) Attach approximately 5 feet of angling twine to the loop to act as a tether for the balloon.

6) Put a few medium-sized pebbles in a small plastic bag and tie to the loop of tape. These will act as stabilizers to keep your balloon upright.

7) Place the hair dryer at the opening of the mouth of the balloon and switch on the hot air mechanism, making sure you move it around constantly so as not to melt the plastic.

8) Tether the balloon once it has been filled with hot air, add or take away pebbles until the structure has a good balance.

9) Unfurl the twine once the tube is stable and fly your solar balloon.

Tips & Warnings

The ideal weather conditions for flying your solar balloon is a cloudless day of full sun with very little wind and slightly cool air. Keep in mind that the colder the outside temperature, the better your balloon will fly.