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.
I have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Abhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
It was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
It has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
My experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
It was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
My experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
About Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
A marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
My experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.