Hot air balloons launch, concluding Chemistry finals

By Alonzo Garza
POST-REGISTER

Using a propane burner launching pad, Lockhart High School Chemistry One students attempted to launch their hand made hot air balloons just outside their classroom on Friday, May 23.

Under the direction of LHS Chemistry teacher Marianne Garcia, the students took a different kind of final exam that included building and launch

ing hot air balloons.

“The class project was designed to evaluate the students ability to apply the knowledge that they learned in chemistry this year,” Garcia said.

Students worked in small teams of three to six and were provided tissue paper, instructions for designing and building a 48-inch balloon and a limited class time to complete their final project.

The project required students to apply their knowledge, skills and abilities to measure, convert measurements and calculate the circumference, radius and volume of their balloon.

Students studied the gas laws of two prominent French scientists who made detailed measurements on how volume of gas was affected by the temperature of the gas. The two scientists were Jacques Charles and Joseph-Louis Gay-Lussac.

From the Charles and Gay-Lussac detailed measurements, students learned that the basic physics behind hot air balloon travel is the effect of increased temperature on the motions of molecules of gas and on the density of the gas. As the temperature increases, the density of the gas decreases.

Garcia’s students also learned about the findings of Robert Boyle, who studied the properties of gases relating the relationship of pressure and volume, known as “Boyle’s Law.” This law explains how an increase of pressure on a gas results in a decrease of volume. This allows students to have smaller cylinders, which contain large volumes of gas such as the propane cylinders used in the launch.

The teams spent the last couple of weeks creating templates for their balloons, measuring and cutting out the panels, gluing them together and then testing their completed balloons.

They tested the balloons for pinholes and rips with a hot air popcorn popper. When holes and weak spots were found students patched them up as they actively discussed the best way to remedy their problems for a successful launch.

Garcia’s students showed great enthusiasm for the project and became increasingly competitive as the days went by. According to Garcia, the competitive spirit was contagious.

The project came to an end and the competition peaked on Friday, May 23 when students attempted to launch their balloons outside of their classroom.

Launch day was busy with students working on last minute repairs and preparation.

Each team was taking additional measurements as well. The measurements were used to make calculations after each launch. The measurements included lift, mass of heated air and conversion to moles, a unit used in chemical conversions.

Despite a windy Friday and limited chances to launch, students had great fun learning about Chemistry in an interesting and interactive way.

There is little doubt that Boyle’s Law and laws of Charles and Gay-Lussac will not be forgotten soon. In fact, an adventurous seed may have been planted and a budding hot air balloon enthusiast may just put Lockhart on the map as far as competitive ballooning is concerned.

Happy ballooning.

agarza@post-register.com