How weather changes - An article by Harshi for her school's magazine
If one thing around us changes every day, it is
possibly the weather. One fine day it is pleasant, another day it is rash. Some
days are warmer, while some days are cooler or rainy. Ever thought why it
happens. Come! Let’s discuss.
Our planet, “The Earth” revolves around “The Sun”, the
only star of our solar system. The changes in weather are caused by the sun.
Sun gives us light and heat. But the amount of heat received from sun is not
same everywhere on the earth, as our earth is tilted on it axis. This heat is
absorbed in the atmosphere of earth. Due to this, air in our atmosphere becomes
warm.
Air near the equator (line which divides the earth in
two equal parts) is warmest as it gets more heat than any other parts of
atmosphere. On the other hand, north and south poles are cold due to being the
farthest points on earth. It means air is hot on some parts of the earth, while
cold on other parts. Air warmed by the sun becomes lighter and rises upwards in
a warm place. Opposite to this in a cold place, air becomes dense and sinks. Hot
air creates low pressure regions, while cold air creates high pressure regions.
Air flows from these high pressure areas towards low pressure regions, thus
creating wind or air current. This is a continuous process as the heat of the
sun is continually received on earth.
Seasons in the northern and southern hemisphere differ
largely due this flow of air. In a high pressure region, water vapor sinks
before it can form the clouds. So, the weather is sunny. In a low pressure
area, water vapor rises and forms clouds resulting in a rain.
Since the earth is tilted, hence at different times of
the year, different parts of the earth surface are closer to sun in comparison
to other parts. Areas close to the poles have very short summer and long
winters. Similarly, areas near the equator have summer all the year. In the
southern hemisphere, summer comes when this part is before the sun. While, in
the northern one at the same time, winter is there.
Therefore, we can understand that all kinds of weather
happen because the air around the earth blows in so many different ways, when
heated by the sun.
Our country is lucky enough to have all kinds of
weather like summer, winter, rain and autumn throughout the year.
Harshi Baijal
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