Weather, Climate and Adaptations of Animals to Climate
Science Class Seven
Learning Goals
In this chapter we will learn about the weather, climate and adaptation of animals to different types of climate, especially in the polar region and rain forests.
Weather
The day to day atmospheric condition of a particular place is called weather.
Weather may change within an hour or may not change for a long time.
If it is said, "it is hot". This means a particular day gets more sunshine.
If it is said, "it is humid". This means, a particular day gets rainfall.
If it is said, "it is hot and humid". This means, a particular day gets more sunshine along with rain.
If it is said, "it is very cold". This means that a particular day has low temperature and gets either no sunshine or very little sunshine.
So, weather keeps changing generally in a short period of time.
Weather Report
Weather report is given on TV, radio, and in newspapers generally on daily basis. One can see the weather report on TV after the news, or in the newspaper.
The weather reports show the maximum and minimum temperature along with moisture present in the air. Moisture present in the air is called humidity.
Weather of the previous day and forecast for the next day or next week are also given in the weather reports. You may have seen the weather report for a particular day.
While observing the weather report, the maximum and minimum temperature, and maximum and minimum humidity can be seen in this. The time for sunrise and sunset for the next day has been also been given. In the report, the forecast for the next day and sometimes for the next week's weather has been given also. Partly cloudy sky, rain, or thundershowers have been forecasted for the next day and next week generally.
Forecast about weather is one of the very difficult tasks. Because the change in weather depends on many factors. The forecast of weather is done by a Government Department called the Department of Meteorology. The person who study and forecast the weather are called Meteorologists. Meteorologists are trained weathermen. Meteorology is a branch of Physics.
Meteorologists collect data from many sources such as satellites and using other many different apparatus. After the collection of data, Meteorologists analyze them and prepare weather reports. On the basis of analysis, Meteorologists also forecast the weather. Satellites are proved a boon in forecasting the weather report.
Importance of weather report:
Although observing a weather report may be boring. But the weather report is very important. Especially in the forecast weather.
The forecasting of weather is very important for farmers, and fishermen.
Forecast of cyclones saves many people. After knowing the forecast of cyclones they go to the safer place.
Elements of Weather
There are some factors that determine the condition of weather. These are temperature, moisture present in the air, speed of the wind, the pressure of air, etc. These are called the elements of weather. Weather at a particular place depends on the elements of the weather.
The amount of sun shining and rainfall also play a very important role to decide the weather of a particular place. Temperature and humidity are important for assessing the weather of a given day.
You may have experienced the decrease in temperature just after and even before the rain. However, we feel more humidity after rain in summer generally.
Cities situated near the sea coast have more humidity present in the air.
Do you know?
Rain gauge is an apparatus used to measure rain fall. It is composed of a measuring cylinder with a funnel on top of it to collect the rain water.
Making of a Weather Forecasting Device
Theory: Cobalt nitrate changes colours with moisture.
Materials required: Thick cardboard, scissors, paintbrush, thread, cobalt chloride.
Activity:
(a) Make an outline drawing of cloud with sun peeping from behind on cardboard.
(b) Cut it out from the outline.
(c) Make a small hole at the top of cardboard so that it can be hanged with a thread.
(d) Paint the drawings with cobalt chloride by applying at least 3 to 4 coats.
(e) Let it dry.
(f) Hang it near a doorway.
(g) When it is sunny outside this weather indicator will look blue in colour.
(h) When it is going to rain this weather indicator will turn into pink.
It happens because cobalt chloride changes colour as per moisture present in the atmosphere.
Climate
The average weather condition of a particular place for a long period is called climate.
The period to decide the climate of a particular place is taken usually not less than 25 years. And after considering the weather condition for such a long period the climate of a particular place is decided.
A Government Department called The Department of Meteorology collects and keeps the records of weather reports of a particular place for many years preserved. After analyzing the weather report for such a long period, the climate of that very place is decided. As Jammu and Kashmir have a cold climate, Kerala has a hot and humid climate, and Rajasthan has a hot climate.
If it is seen that most of the time, that is throughout a year the temperature is high, then the place is called hot. If there is more rainfall with high temperatures most of the time throughout the year, then the climate is called hot and humid. Similarly, if there is a low temperature for a long time throughout the year, the climate of the place is called cold.
When you will observe the weather report of India for a long period, you will see that most of the time the temperature in India is high and it receives more rainfall. So, the climate of India is hot and humid. However as India is a vast country, hence at some places the climate is cold while in some places the climate is hot and humid. In general, India has a hot climate.
Climate of a particular place remains relatively constant while the weather can change daily. "Climate is what you expect, the weather is what you get" is a popular phrase that defines the climate and weather.
Climate of a particular place depends on many things. Some important factors that decide the climate of a particular place are being given here.
Latitude
Latitudes are the imaginary lines on the earth parallel to the equator. It ranges from 00 to 900. Equator is considered as OO. By knowing the latitude we can know the distance of a particular place from the equator. Since the equator receives more sunlight throughout the year hence, a place closer to the equator receives more sunshine and a place farther to the equator receives less sunshine throughout the year. So, a place that is closer to the equator is warmer and that which is farther to the equator is colder.
Altitude
Altitude or height is measured from the sea level. Temperature decreases with an increase in altitude. Places situated at higher altitudes are colder compared to places situated at lower altitudes. Hence, altitude also influences the climate of a place. Mount Kenya, which is in Africa is snow-capped throughout the year because of its high altitude.
Wind
Wind also influences the climate. In India, the Monsoon, a type of wind that brings rain, is very important for agriculture based country like India.
Large water bodies
Place situated near the large water bodies, such as coastal area has uniform weather throughout the year and has moderate climate because of land and sea breeze.
Mountains and Rainfall
'Mountains bring rains' is an old proverb. When wind travels, the slope of mountain ranges compels air to rise high. By going up, i.e. increasing in altitude, the temperature decreases. With the decrease in temperature, the moisture present in the air gets condensed and falls as rain or snow.
The place that is another side of the mountain from the way of wind does not get rainfall and is dry and hot. Such a place is called situated under rain shadow. Rajasthan is situated in the rain shadow of the Arawali Hills and has a hot and dry climate. Hence, mountains affect the rainfall, which affects the climate. North-Eastern India receives more rainfall because of the Himalaya range of mountains and has a wet climate.
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