Students from Michael McGlinn’s eighth grade science classes have been working on completing tissue paper hot air balloons, which culminates a unit on density. Cecilia Aguila, Lily Goldstein and Sophie Robinson, students in one of Michael’s classes, wrote about the experience of the latest hot air balloon test.

“On January 3, our class tested our new hot air balloons in an experiment that coordinated scientific understanding and creative skills. During the weeks leading up to this experiment we had several test runs. In November and December, we worked in groups to create hot air balloons out of tissue paper, glue and wire using the lessons we learned on density earlier in the year.

For heating the air in the balloon, we used a camp stove and other flammable gases and put the opening of the hot air balloon over the chimney of the stove. As the hot air flowed into the balloon, it began to expand. As the air is heated, the molecules start to push away and separate from each other. This increased the volume of the balloon, which decreased the density. Because the heat inside of the balloon was less dense than the cold air surrounding it, it flew into the sky when we let go.”