Significance Of Atmospheric Pressure


 
 
Concept Explanation
 

Significance Of Atmospheric Pressure

Atmospheric Pressure, Winds and Air Masses: Air, being a physical substance, is an admixture of several gases present in the atmosphere and, thus, it has its weight. Air pressure is defined as total weight ofamass of column of air above per unit area at sea level (unit area being one square inch, in square foot, one square centimetre, one square metre etc.). The atmospheric pressure is the highest at sea level. It exerts the weight of 14.7 pounds on the area of one square inch at sea level or 1,034 grams (about one kilogram) per square centimetre. One can imagine as to how much weight of overlying air is being carried by every man daily, but he does not feel such enormous weight on his head and shoulders because the air present inside human body exerts equal amount of outward pressure which balances the inward atmospheric pressure.

Measurement of Air Pressure: The atmosphere rests on the earth's surface owing to the gravitational pull of the earth. Hence, it exerts its weight as pressure on the earths' surface. Atmospheric pressure is thus the weight of the column of air at any given place and time. It is measured by means of an instrument called a barometer. It is measured As a force per unit area. The units used by meteorologists for this purpose are called millibars (mb), One millibar is equal to the force of one gram on a square centimetre. A pressure of 1,000 millibars is equal to the weight of 1.053 kilograms per square centimetre. In other words, it will be equal to the weight of a column of mercury 75 centimetres high, To be exact, the normal pressure at sea level is about 76 centimetres (1,013.25 millibars). However, it fluctuates on either side of this value.

The distribution of atmospheric pressure is shown on a map by isobars. An isobar is an imaginary line drawn through places having equal atmospheric pressure reduced to sea level. The spacing of isobars expresses the rate and direction of the pressure changes and is referred to as pressure gradient. Close spacing of isobar indicates a strong pressure gradient, while wide spacing suggests a weak gradient. The pressure gradient, therefore, may be defined as the decrease in pressure per unit distance in the direction in which the pressure decreases most rapidly. There are two types of pressure systems - high pressure and low pressure.

Chapters
Pre-Historic Period
Indus Valley Civilization
Vedic Civilization
Religious Reform Movement
The Early Kingdoms
The Mauryan Empire
Post Mauryan Period
The Age Of The Guptas
Post Gupta Era
Age of Rajput
Khilji Dynasty
Slave Dynasty
Tughlaq and Sayyid Dynasty
Vijaynagar Empire And Bahamani Kingdom
Mughal Empire And Beyond
Lodhi Dynasty
Cholas, Chalukyas and Pallavas
Arab Invasions
Bhakti and Sufi Movement
Rise of Sikhs, Jats and Marathas
Administrative Structure of Delhi Sultanate
Architecture During Medivial India
Advent Of The Europeans
Post Mughal Period
Rise of New States in 18th Century
Growth of British Paramountacy
Socio Religious Reforms
Constitutional Development of India
Indian Struggle Against British Rule
The Revolt Of 1857
Education Under British Rule
Role of Press in Freedom Struggle
First Phase of National Movement
Second Phase of National Movement
Third Phase of National Movement
Constitutional Development in India
Constituent Assembly
Union And Its Territory
Structure of Indian Constitution
Fundamental Rights and Duties
The Union Executive
The Union Legislature
Constitutional Amendments and Provisions
Judiciary In India
Emergency Provisions
Center - State Relations
The State Executive
The State Legislature
Election Commission Of India
Constitutional Organisation
Non-Constitutional Organisation
Local Self Goverment
India - Size And Location
Geological History Of India
The Physical Features Of India
Climate Of India
Soils In India
Natural Vegetation
Windlife Conservation In India
Drainage System of India
Irrigation System Of India
Agriculture In India
Livestock And Fisheries In India
Minerals And Energy Resources In India
Means Of Transport In India
Major Industries In India
Tribes of India
Census of India 2011
Music
Dance
Theatre
Pantings
Art, Architecture & Culture of India
Bio-Diversity
Earth And Its Structure
Land Rock And Soil
Atmosphere, Climate And Weather
Oceanography
Human And Regional Geography
Economic Growth And Development
Sectors Of Indian Economy
Economic Planning Of India
Fiscal And Monetary Policy In India
Infrastructure In India
Effects Of British Rule On Indian Economy
National Income
Banking System In India
Poverty And Unemployment
Inflation And Trade Cycles
Major Institutions
Environmental Studies
Tissues In Organism
Cytology
Classifucation Of Plants
Structural Composition Of Plants
Nutrition In Plants, Harmones And Plant Disease
Ecosystem
Classification In Animals
Nutrition In Animals
Human Digestive System
Human Respiratory System
Human Skeleton System
Human Excretory System
Human Nervous System
Human Circulatory System
Human Endocrine System
Human Reproductive System
Genetics
Human Diseases
States Of Matter
Metals And Non Metals
Acid Bases And Salts
Element Compounds And Mixture
Physical And Chemical Change
Carbon And Its Compounds
Periodic Classification
Fuel, Combustion And Flame
Environmental Chemistry
Rest And Motion
Work Power And Energy
Gravitation
Pressure And Its Effects
Simple Harmonic Motion
Sound and Waves
Heat And Temperature
Light - Reflection
Electricity And Magnetism
Modern Physics
Science And Technology
Force And The Laws Of Motion
Light - Refraction
Dispersion And Human Eye
Magnetic Effect Of Electric Current
Atom And Molecule
Chemistry In Everyday Life
Units And Dimensions
Content / Category
Class / Course
 
 


Students / Parents Reviews [20]