Weather balloons, which are made of latex or synthetic rubber (neoprene), are filled with either hydrogen or helium. An instrument called a radiosonde is attached to the balloon to measure pressure, temperature and relative humidity as it ascends up into the atmosphere.

Do they still use weather balloons?

Fast forward to today, the National Weather Service now has 92 sites where balloons are turned loose each day. “Weather balloons have gone through dozens of upgrades over the past 150 years. Radiosondes that used to weigh a few pounds are now just a few ounces.

The first weather balloons came into existence in France in 1892. Devices aboard measured barometric pressure, temperature and humidity but had to be retrieved in order to collect the data. These large balloons inflated with gas and remained open at the bottom like a hot-air balloon.

What makes weather balloons fly?

A measured amount of helium is put into the balloon that will give it enough lift to get off the ground and ascend to the desired float altitude. As the balloon rises, the gas inside the balloon expands because the atmospheric pressure surrounding the balloon drops.

Weather balloons can rise to an altitude of 24 miles (39 kilometers) or more before they burst, and a payload may land (via parachute) up to 75 miles (120 km) away, depending on wind conditions at the launch site, Maydell said.