A weather balloon just after it was launched by students and their teachers of the Northern Arizona University. Weather balloons typically reach an altitude of circa 30,000 meter (100,000 feet) before they burst. The payload packages are retrieved, the data are downloaded, and the teachers' classes analyze the resulting data about the structure of the Earth's atmosphere. Note the parachute below the balloon and the instrument boxes distributed over the rest of the string.
[Image borrowed from coe.nau.edu]