Notes On Weather and Climate - CBSE Class 7 Science
The day-to-day conditions of the atmosphere at a place with respect to elements like temperature, humidity, rainfall, wind speed, etc. is called the weather of that place. Changes in weather are observed in the atmosphere. The atmosphere is all around us – we cannot see it, but it keeps us warm. Without it, the earth would be a lifeless ice ball. In addition, the atmosphere absorbs or deflects the incoming ultraviolet rays and other charged particles. Constituents of weather Weather is made up of elements like rainfall, temperature, humidity, wind speed, snow, thunder and lightning. Factors effecting weather The sun is responsible for all the changes in the weather. We know that the sun is a huge sphere of hot gases and has a very high temperature. The distance between the sun and us is very large. The sun is the chief source of light and heat for the earth. It is also the primary source of energy, and causes changes in the weather. The energy absorbed and reflected by the earth’s surface, the oceans and the atmosphere play an important role in determining the weather at any place. Also, gases like carbon dioxide, methane and water vapor play a role in determining the weather. Place and weather The weather in coastal areas is very different than that in a desert or hilly areas. The maximum and the minimum temperatures of a place are recording using a special type of thermometer every day. Special thermometers called maximum and minimum thermometers are used to determine the maximum and the minimum temperatures in a day. The maximum temperature of the day is recorded during the afternoon, while the minimum temperature is recorded early in the morning. Measuring the components of weather Different types of measuring instruments are available to measure different weather components like temperature, rainfall, windspeed, humidity etc. Measuring temperature of a place The change in the temperature of the day. The temperature is low early in the morning, and increases by noon. It decreases again towards the evening, and the cycle continues. The instrument useful to measure the temperature of a place is thermometer. Inorder to measure the highest and lowest temperature of a place is maximum minimum thermometer (MMT). Measuring rainfall In general meterologists measures the rainfall by using a "Rain gauge" also called as Ombrometer or Puliometer expressed in centimeters or millimeters. Measuring the direction of wind The direction of wind and speed  by using Anemometer. Measuring humidity of a place " Quantity of moisture in the air is the humidity of the place". It feels more sweaty when humidity is high and high temperature. Climate of a place In winters, it gets dark early. Meteorologists record the weather every day. The records of the weather are preserved for several decades. These records helpful to determine the pattern of the weather at a place. The average weather pattern taken over a longer time is called the climate of the place. The mean temperature for a given month is found in two steps. First, we find the average of the temperatures recorded during the month. Next, we calculate the average of such temperatures over many years. The result is the mean temperature. Mean temperature helps compare the weather at two different places. For example, if we compare the temperatures of Thiruvananthapuram in Kerala and Srinagar in Jammu and Kashmir, we can conclude that Thiruvananthapuram is very hot and wet than Srinagar, which is moderately hot and wet for some parts of the year. Consider another place like Rajasthan, which has high temperatures during most parts of the year, but very low temperatures in winter, which lasts for a few months. This region receives scanty rainfall. Therefore, it is known as typical desert climate. North-eastern India receives rain for a major part of the year. Hence, we can say that the climate of the region is wet.

#### Summary

The day-to-day conditions of the atmosphere at a place with respect to elements like temperature, humidity, rainfall, wind speed, etc. is called the weather of that place. Changes in weather are observed in the atmosphere. The atmosphere is all around us – we cannot see it, but it keeps us warm. Without it, the earth would be a lifeless ice ball. In addition, the atmosphere absorbs or deflects the incoming ultraviolet rays and other charged particles. Constituents of weather Weather is made up of elements like rainfall, temperature, humidity, wind speed, snow, thunder and lightning. Factors effecting weather The sun is responsible for all the changes in the weather. We know that the sun is a huge sphere of hot gases and has a very high temperature. The distance between the sun and us is very large. The sun is the chief source of light and heat for the earth. It is also the primary source of energy, and causes changes in the weather. The energy absorbed and reflected by the earth’s surface, the oceans and the atmosphere play an important role in determining the weather at any place. Also, gases like carbon dioxide, methane and water vapor play a role in determining the weather. Place and weather The weather in coastal areas is very different than that in a desert or hilly areas. The maximum and the minimum temperatures of a place are recording using a special type of thermometer every day. Special thermometers called maximum and minimum thermometers are used to determine the maximum and the minimum temperatures in a day. The maximum temperature of the day is recorded during the afternoon, while the minimum temperature is recorded early in the morning. Measuring the components of weather Different types of measuring instruments are available to measure different weather components like temperature, rainfall, windspeed, humidity etc. Measuring temperature of a place The change in the temperature of the day. The temperature is low early in the morning, and increases by noon. It decreases again towards the evening, and the cycle continues. The instrument useful to measure the temperature of a place is thermometer. Inorder to measure the highest and lowest temperature of a place is maximum minimum thermometer (MMT). Measuring rainfall In general meterologists measures the rainfall by using a "Rain gauge" also called as Ombrometer or Puliometer expressed in centimeters or millimeters. Measuring the direction of wind The direction of wind and speed  by using Anemometer. Measuring humidity of a place " Quantity of moisture in the air is the humidity of the place". It feels more sweaty when humidity is high and high temperature. Climate of a place In winters, it gets dark early. Meteorologists record the weather every day. The records of the weather are preserved for several decades. These records helpful to determine the pattern of the weather at a place. The average weather pattern taken over a longer time is called the climate of the place. The mean temperature for a given month is found in two steps. First, we find the average of the temperatures recorded during the month. Next, we calculate the average of such temperatures over many years. The result is the mean temperature. Mean temperature helps compare the weather at two different places. For example, if we compare the temperatures of Thiruvananthapuram in Kerala and Srinagar in Jammu and Kashmir, we can conclude that Thiruvananthapuram is very hot and wet than Srinagar, which is moderately hot and wet for some parts of the year. Consider another place like Rajasthan, which has high temperatures during most parts of the year, but very low temperatures in winter, which lasts for a few months. This region receives scanty rainfall. Therefore, it is known as typical desert climate. North-eastern India receives rain for a major part of the year. Hence, we can say that the climate of the region is wet.

#### Activities

Activity1: Oceanservice.noaa.gov has developed an interactive simulation to guide the knowledge of weather and climate of a different places of the world. The difference in colours will give you basic information of a particular place. Go to Activity Activity2: Lessons.e-learningforkids.org has developed an interactive simulation regarding weather and climate starting from the basic levels of understanding the concept. Followed by questions which involves drag and drop of images in respective places of weather conditions, this enables you to move into next level. Go to Activity Activity3: Cotf.edu has developed an interactive quiz and questions are based weather and climate. Each question is followed by explanation.  Go to Activity

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