- Weather balloons consist of two parts: the balloon itself and an instrument package called a radiosonde. The radiosonde contains sensors that probe the pressure, temperature and humidity in the air. According to the National Weather Service, weather balloons are filled with hydrogen or helium. The balloon itself is usually about four feet wide.
- Before launching weather balloons, meteorologists fill them with hydrogen or helium and attach the radiosonde. The balloon must also have a parachute attached so that the radiosonde can fall safely if the balloon breaks. Once the balloon is ready, it is released into the air.
- Weather balloons float because they are filled with gas that is lighter than air. According to the University of Hawaii chemistry department, any gas that is lighter than air will cause a balloon to float just as an object that is less heavy than water will float upon the water. It claims that, theoretically, weather balloons could float if filled with hydrogen, helium, methane or hot air. However, balloons are most commonly filled with helium. Hydrogen and methane are not practical choices because they ignite easily, causing explosions. According to the department, hot air is also not a practical choice because it can only lift small items.
- The National Weather Service states that weather balloons last in excess of two hours. As the balloon floats, the gas inside it expands, causing the balloon itself to expand. When the balloon expands beyond its limit (about 20 feet, according to the National Weather Service), it bursts.
- Weather balloons are built with parachutes attached to the radiosondes to ensure safety. When a balloon bursts, the parachute helps slow the descent of the radiosonde so that it can land safely, with a minimum of harm to people or property.
previous post
next post