What is the Troposphere?
The troposphere the lowest layer of the atmosphere that is where all the weather conditions take place. It is made up of 80% Nitrogen, 19% Oxygen, less than 1% Argon, and less than 1% of Carbon Dioxide. The troposphere is 7-11 miles thick. Most of the mass (75-80%) of the atmosphere is made up of the troposphere.
The air is warmer near ground level of the troposphere. The air gets colder the higher up the troposphere goes. That is why tall mountain peaks can still contain snow in the summertime. The air pressure and density also decreases with altitude. That is why high flying aircraft's are pressurized.
Weather Balloons
Weather balloons were first invented in 1896 France. Those experiments soon led to the discovery of the troposphere. Weather balloons are sent out into the troposphere to collect data such as atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde. To obtain wind data, they can be tracked by radar, radio direction finding, or navigation systems.