Weather balloons are used daily to carry meteorological instruments to 20 miles (30 kilometers) and above into the atmosphere to measure temperature, pressure, humidity, and winds. The balloons are made of rubber and weigh up to 2.2 pounds (one kilogram). More than 200,000 weather soundings are made with such balloons worldwide each year.

Credits - National Center for Atmospheric Research, University Corporation for Atmospheric Research, National Science Foundation