Weather balloons are large, inflatable balloons filled with helium or hydrogen that carry instruments high into the atmosphere. These instruments, known as radiosondes, measure various weather conditions, such as temperature, humidity, and air pressure. As the balloon rises, it collects valuable data that helps meteorologists understand weather patterns and make forecasts. Once the balloon reaches a certain altitude, it expands and eventually bursts, allowing the radiosonde to fall back to Earth with a parachute. This process provides crucial information for predicting storms, understanding climate change, and improving safety during severe weather events.