Weather balloons are large, inflatable balloons filled with helium or hydrogen that carry instruments to measure atmospheric conditions. These instruments collect data on temperature, humidity, pressure, and wind speed as the balloon ascends into the atmosphere. The information gathered helps meteorologists predict the weather and understand climate patterns. As the weather balloon rises, it expands due to decreasing air pressure until it eventually bursts, usually at altitudes of around 100,000 feet. The instruments, called radiosondes, then fall back to Earth, often equipped with parachutes to ensure a safe landing. This process is crucial for improving our understanding of the Earth's atmosphere.