GEOLOGY

Detailed explanation-1: -As altitude increases, the amount of gas molecules in the air decreases-the air becomes less dense than air nearer to sea level. This is what meteorologists and mountaineers mean by “thin air.” Thin air exerts less pressure than air at a lower altitude.

Detailed explanation-2: -The density of air decreases with height. There are two reasons: at higher altitudes, there is less air pushing down from above, and gravity is weaker farther from Earth’s center. So at higher altitudes, air molecules can spread out more, and air density decreases (Figure below).

Detailed explanation-3: -The more air molecules in once space, the denser the air. As air gets warmer, the air molecules have more energy. All these hot, energized molecules will move around everywhere, increasing the speed of the air, losing density. Since the molecules are going off everywhere, the air becomes less dense.

Detailed explanation-4: -As the molecules heat and move faster, they are moving apart. So air, like most other substances, expands when heated and contracts when cooled. Because there is more space between the molecules, the air is less dense than the surrounding matter and the hot air floats upward.

Detailed explanation-5: -As we go higher in the atmosphere, atmospheric pressure drops and the air goes on getting thinner. That’s why mountain climbers sometimes need bottled oxygen to breathe. It becomes difficult to breath as the air is thinner.