ICSE Class 9 Answered
Discuss the factors affecting atmospheric pressure with respect to the following:
Temperature
Altitude
Water Vapour
Rotation of the Earth
Asked by Topperlearning User | 07 Jan, 2015, 09:10: AM
Expert Answer
- Temperature: When the temperature of a place increase, the atmospheric pressure decreases. This is because, increase in temperature results in the heating of the air. Warm air expands. The molecules of the warm air become less dense and hence exert less pressure. On the contrary, a decrease in temperature makes the air cool and dense. This creates a high pressure area in a region.
- Altitude: The atmospheric pressure decreases with an increase in altitude. Air is compressible. As the gravity of the Earth, pulls the molecules and gases towards the ground, the lowest layer of the air get densest. This dense layer of air exerts the greatest pressure.
- Water Vapour: Moist air exerts more pressure as it contains fewer amounts of nitrogen and oxygen. Dry air on the other hand, exerts less pressure as it has greater amount of nitrogen and oxygen and hence is denser.
- Rotation of the Earth: The rotation of the Earth causes the air at the Poles to be pushed away towards the Equator. In theory, the air should have accumulated at the Equator creating a high pressure belt. However, this does not happen. On the contrary, the air gets heated up at the Equator, gets warmer and rises up creating a low pressure belt.
Answered by | 07 Jan, 2015, 11:10: AM
