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