- Q) How do weather and climate influence life ?
A: Weather and climate influences our ways of life- the clothes we wear, the houses we live in, the crops we grow and so on.
- Q) State any three factors that determine the climatic conditions of a geographical location?
A: The factors that determine the climatic conditions of a geographical location are rainfall, temperature, humidity and wind speed.
- Q) Define the following terms: (i) weather and (ii) climate
A: Weather is the condition of the atmosphere at a particular place over a short period of time. Climate refers to the average weather conditions of a large area over a long period of time, say 25 to 30 years.
- Q) What is humidity?
A: The amount of water vapour present in the atmosphere is called humidity.
- Q) What is absolute humidity?
A: It is the actual amount of water vapour in a given volume of air at a given temperature. It is measured in grams per cubic metre.
- Q) What is relative humidity?
A: It is the ratio between the actual amount of water vapour in a given volume of air and the maximum amount of water vapour that the same volume of air can contain at the same temperature. It is expressed in percentage.
- Q) What is a rain gauge used for?
A: Rain gauge is used to measure rainfall. The unit of rainfall is centimeter or milimetre.
- Q) What is precipitation?
A: Continuous condensation of water vapour in the air results in the formation of minute droplets of water. When these droplets join together, they form bigger drops, which become too heavy to float and start falling down. This process is called precipitation.
- Q) List the various forms of precipitation?
A: There are four forms of precipitation : rain, snow, sleet and hail.
- Q) Write the forms of condensation?
A: The forms of condensation are clouds, dew, frost, fog and mist.
- Q) What are clouds?
A: Clouds are extreme small and light accumulations of drops of water or crystals of ice that remain suspended in the air.
- Q) Write types of clouds?
A: Based on their appearance, height at which they occur and their characteristics clouds can be classified as Cirrus clouds, Cumulus clouds, Stratus clouds, Nimbus clouds.
- Q) What is Dew ?
A: Dew is the tiny drops of water formed on exposed objects, such as grass, leaves and plants, during the night.
- Q) What is frost?
A: Frost is ice crystals formed from moisture in the air at temperature below freezing point (0 c or 32 F) that condenses on grass, leaves and plants.
- Q) What is Fog ?
A: Fog is a danse cloud cover that forms very close to the ground or water bodies, instead of in the sky.
- Q) What is Mist?
A: Mist is less intense fog.
- Q) What is rain?
A: When the condensed water vapour in the clouds falls down and is visible to the naked eye in the form of drops of water, it is known as rain.
- Q) What is drizzle ?
A: When the drops of rain are very small, it is called drizzle.
- Q) What are westerly and easterly winds ?
A: The wind gets its name from the direction from which it blows. Winds blowing from the west are called westerly winds and those blowing from the east are called easterly winds. These winds influence rainfall and surface currents of the ocean.
- Q) What is Coriolis effect?
A: The rotation of the Earth makes winds deflect from their original path. This deflection due to the Earth’s rotation is called the Coriolis effect.
- Q) What is Ferrel’s Law?
A: Winds get deflected to their right in the Northern Hemisphere and to their left in the Southern Hemisphere. This is known as Ferrel’s Law.
- Q) What is a Beaufort Scale?
A: A Beaufort Scale, also known as Beaufort Wind Force Scale, is used to measure wind velocity based on the observed sea conditions.
- Q) List the major pressure belts of the earth.
A: There are four major pressure belts on the Earth as
- The equatorial low pressure belt (5oN to 5oS )
- The sub-tropical high pressure belt (30oN & S to 35oN & S)
- The sub-polar low pressure belt (60oN & S to 65oN & S)
- The polar high pressure belt (90o N & S)
- Q) What is sunshine hours?
A: The amount of sunshine that a geographical location receives has a direct influence on its temperature. This amount is measured in sunshine hours.
Fill Up the Blanks.
- The temperature of the atmosphere can be defined as the degree of hotness or coldness of air.
- The instrument used to measure temperature is called thermometer.
- Scientific study of weather conditions is called meterology .
- Scientists who study weather are called meteorologists.
- The predictions, which are announced by weather stations, are collectively known as weather forecast.
- The difference between the maximum and the minimum temperatures recorded in a year is called the diurnal range of temperature.
- The average of maximum and minimum temperature recorded in a day is mean daily temperature.
- The difference between the maximum and minimum temperature recorded in a year is called the annual range of temperature.
- The average of mean temperature for twelve months is mean annual temperature.
- The freezing point of alcohol is -115o
- The boiling point of alcohol is 357o
- The two most commonly used scales to measure temperature are Celcius (oC) and Farenhite (oF).
- Weather stations normally use the Stevenson Screen, an instrument shelter, to protect their thermo meters from rain.
- The instrument used to measure the atmospheric pressure is called
- There are two types of barometers : mercury barometer and aneroid barometer.
- The unit of measurement of pressure is milibars (mb).
- The normal pressure at sea level is 1013 mb.
- When pressure is less than 1013 mb it si called low pressure and when more than 1013 mb is called high pressure.
- Horizontal movement of air from one place to another is called
- The instrument used to measure the direction of wind is called a wind vane.
- The anemometer is an instrument used to measure the speed of wind.
- The speed of wind is measured in knots.
- 1 knot = 1 nautical mile/hour.
- Force exerted by a column of air due to its weight, at a particular place on the Earth’s surface is called Atmospheric pressure.
- Weather studies are carried out by ballons and
- Every square inch of our bodies is constantly under pressure from the Earth’s atmosphere with a force of 1kgcm-2 .
- 1 kg/cm2 = 7 lb/in2
- The force on 1000 cm2 (a little larger than a square foot) is about a ton!
- Status clouds found above 2000 m of altitude.
- Nimbus clouds found at altitude below 2000m.