Jay Thompson's Principles of Technology class has been at it again. In the past, they've build model cars, kites and rockets. This time it was hot air balloons.To illustrate buoyouncy, density, and Archimedes' Principle, Thompson had his students construct and launch balloons they'd built themselves last week.
Using 18-24 sheets of tissue paper, and a glue stick, the kids formed a balloon around an upside down umbrella. They carefully glued the sheets together, as neatness contributes to a longer balloon flight. Next, they decorated the balloons to add to the fun of the project. The entire construction process took two days of class time.
On the third day, the model hot air balloons were launched outside the school. The class connected a pipe to a lit camp stove. The balloons were then held over the pipe for three to four minutes in order to fill them with hot air. Next, they released the balloons and watched them fly.
Jon Lieser, Dustin Hoppe (hidden), and Karl Ainsley fill a tissue-made balloon with hot air.
Students used stopwatches to record the length of each flight. The longest flight this year was 55 seconds long. In past years, the balloons have stayed airborne for over three minutes. Trigonometry was also used with information from the flight to calculate the height the balloons reached.
Thompson said his classes get the best results with this project on cold days, due to contrasting air densities between the warm air in the balloons and the cold air outside. He also said bigger balloons travel futher. The biggest ballon he's had in the project's history was made with 45 sheets of tissue paper. It traveled from the school to the golf course.
"This is a good project for kids because it's fun, and it builds cooperation within groups," said Thompson. The idea came from a physics teacher in New York state, where Thompson lived and worked for seven years.
The Principles of Technology class is a year-long course open to juniors and seniors.