We have been launching high-altitude balloons to engage students in science since 2013. Our custom balloon kit allows high school teachers and students to collect environmental data and capture videos. Through our experience interacting with high school students, we have found that the high-altitude balloon experiment is an effective tool for inquiry-based learning to introduce chemistry topics including gas properties, elements and molecules, heat capacity, thermochemistry, electromagnetic radiation, bond breaking and formation, and atmospheric chemical reactions. Examples are given to demonstrate how to incorporate the experiment in high school science classrooms.