Water cycle
Weather
We see that the weather changes almost everyday. Some days are hot and uncomfortable; some days are pleasant and cool. Some days are cold and chilly. Some days are rainy. These changes affect our lives. The weather depends upon the sun, wind, clouds and rain.
Evaporation
We have seen in our everyday life that out wet clothes gets dry when put out in the sun and breeze. All this happens due to evaporation. Evaporation is the process by which a liquid changes in to vapors at all temperature. These vapors go up in to the atmosphere.
Factors affecting evaporation
a) If the temperature of the liquid is high, it evaporates faster.
b) evaporation is faster if the exposed area of surroundings is large
c) evaporation is faster if there is a wind blowing over the liquid
Condensation
The water stored in ponds, Lake Etc. gets heated up due to sun. It goes on changing into vapors. These vapors get in to the atmosphere. When cooled, these vapors change back I to water. This process of changing vapor in to liquid is called condensation.
Water evaporates constantly from ponds, lakes, rivers and oceans. Vapors move upwards and come in contact with smoke and dust particles. Then they condense to form tiny drops. These droplets float in air. More and more droplets come closer to each other. This collection of suspended tiny drops is called a cloud.
As clouds become collar, they condense and become heavier. They fall back to ground in from of the rain. Water completes a full cycle. This cycle is called the water cycle.
Hail stones, Fog, dew drops
When the drops of rain pass through a very cold region, they freeze and fall in the form of snow or hail stones.
When it is quite cool near the surface of the earth in winter, the eater vapors present in the air get condensed on smoke and dust. These condensed droplets from the fog.
The water vapors condense on the leaves of plants when the temperature is low. They form dew drops on the leaves.
Weather affects us in many ways
In summer when it is very hot, we do not feel like going out. Outdoor activities are decreased. We wear light and soft colored clothes. In winter we like to sit and play in the sun. We bate in hot water. We wear heavy woolen clothes.
Cloudy and rainy days are cooler than sunny days. Cloudy nights are warmer than clear nights. Foggy weather disturbs the movements of vehicles.
The hot wind ``loo’ blowing during the summer is very uncomfortable. Chilly wind during winter is also uncomfortable.
Weather forecasting
As changes in weather affect our lives, we have a meteorological department to forecast the weather. To judge or predict the type of weather in advance is called weather forecasting. It is very important for farmers, airmen, navigators and fishermen.