Grade 7 Geography: Climate and Weather Chapter

ICSE Grade 7 Geography

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Grade 7 Geography: Climate and Weather Chapter by Mind Map: Grade 7 Geography: Climate and Weather Chapter

1. meteorology

1.1. study of

1.1.1. weather

1.1.2. its elements

2. diff b/w weather and climate

2.1. weather

2.1.1. short term atmospheric conditions

2.1.2. existing in a

2.1.2.1. given time

2.1.2.2. given area / particular statuion

2.1.3. can change in a short period

2.1.4. influenced by

2.1.4.1. temperature

2.1.4.2. humidity

2.2. climate

2.2.1. aggregate over long period of time

2.2.2. day to day weather conditions

2.2.3. refers to a large area

2.2.4. collective effect of all its elements

3. elements of weather and climate

3.1. 1. temperature

3.1.1. heating of earth and atmosphere

3.1.1.1. solar radiation is the only permanent and continuous source of heat

3.1.1.1.1. process of giving out energy by the sun

3.1.1.2. insolation

3.1.1.2.1. amt of solar radiation received on earth's surface

3.1.1.2.2. received as short waves

3.1.1.2.3. does not heat the atmosphere

3.1.1.2.4. varies from place to place, depends on

3.1.1.3. terrestrial radiation

3.1.1.3.1. heat is reflected back by the earth's surface

3.1.1.3.2. long wave radiations

3.1.1.3.3. heats up the atmosphere

3.1.2. measurement

3.1.2.1. measured with the help of a thermometer

3.1.2.1.1. made out of glass tube

3.1.2.1.2. mercury in it which expands on heating and contracts on cooling

3.1.2.1.3. scale of a thermometer

3.1.2.1.4. Six's thermometer

3.1.2.2. types

3.1.2.2.1. daily range

3.1.2.2.2. Average / mean temperature

3.1.2.2.3. annual range

3.1.3. isotherms

3.1.3.1. lines imaginary lines drawn to connect location having same temperature

3.2. 2. atmospheric pressure

3.2.1. force exerted

3.2.1.1. by vertical column of air

3.2.1.2. per unit of surface area

3.2.2. air has weight due to great height of atmosphere

3.2.3. factors effecting

3.2.3.1. altitude

3.2.3.1.1. pressure exerted decreases with increase in height

3.2.3.1.2. decrease by 1 cm of mercury per 110 metres of ascent

3.2.3.1.3. highest at sea level

3.2.3.2. temperature

3.2.3.2.1. decreases with increase in temperature

3.2.4. pressure belts

3.2.4.1. created by (main factors)

3.2.4.1.1. unequal heating of

3.2.4.1.2. rotation of the earth

3.2.4.2. typically

3.2.4.2.1. high temperature

3.2.4.2.2. low temperature

3.2.4.3. permanent pressure belts

3.2.4.3.1. Equatorial Low (doldrums)

3.2.4.3.2. Sub Tropical High

3.2.4.3.3. Sub Polar Low

3.2.4.3.4. Polar High

3.2.5. measurement

3.2.5.1. measured with the help of a barometer

3.2.5.1.1. simple barometer

3.2.5.1.2. aneroid barometer

3.2.5.1.3. ranges

3.2.5.2. measured in

3.2.5.2.1. cm of mercury

3.2.5.2.2. inches of mercury

3.2.5.2.3. millibars (mb)

3.2.5.3. altimeter

3.2.5.3.1. height of an airplane during its flight

3.2.5.3.2. barograph

3.3. 3. humidity

3.3.1. definition

3.3.1.1. amount of water vapour in the air

3.3.1.2. related to temperature of air

3.3.2. expressed as

3.3.2.1. absolute humidity

3.3.2.1.1. amount of water vapour

3.3.2.1.2. per cubic metre of air

3.3.2.1.3. e.g. 20 gm / cubic metre

3.3.2.2. relative humidity

3.3.2.2.1. ratio of

3.3.2.2.2. expressed as % e.g. 25%

3.3.2.2.3. air saturation

3.3.3. measurement

3.3.3.1. relative humidity is most commonly used for measuring humidity

3.3.3.1.1. saturated air has a relative humidity of 100%

3.3.3.1.2. dry air has a relative humidity of 0%

3.3.3.2. measured with the help of a hygrometer

3.3.3.2.1. wet and dry bulb thermometer

3.4. 4. precipitation

3.4.1. process by which water falls down from the atmosphere to the earth

3.4.1.1. no change of state of water, only location - from atmosphere to ground

3.4.1.2. occurs when tiny droplets join to form larger droplets to fall to the ground

3.4.2. types of precipitation - determined by temperature inside and outside the clouds

3.4.2.1. rain

3.4.2.1.1. precipitation in liquid form

3.4.2.1.2. most common form of precipitation

3.4.2.2. hail

3.4.2.2.1. precipitation in frozen lumps of ice

3.4.2.2.2. form inside tall cumulonimbus clouds

3.4.2.3. dew

3.4.2.3.1. precipitation in tiny water droplets which condenses on cool surfaces

3.4.2.3.2. occurs on calm clear cold nights

3.4.2.4. snow

3.4.2.4.1. precipitation in the form ice crystals

3.4.2.4.2. at high latitude and mountain regions

3.4.3. rain is shown by isohyet

3.4.3.1. imaginary line

3.4.3.2. passes through places with same rainfall

3.4.4. how is rain shown on a map?

3.4.5. measurement

3.4.5.1. measured by a rain gauge

3.4.5.1.1. rain water collected through funnel for 24 hrs

3.4.5.1.2. water measured with a measuring glass

3.4.5.1.3. kept slightly above the ground (30 cm)

3.4.5.2. measured in millimeters(mm)

3.4.5.3. instrument providing continuous record of rainfall- hyetograph

3.4.5.4. snow or hail measured by melting them into water

3.5. 5. wind

3.5.1. air which moves from places with high pressure to places with low pressure

3.5.2. characteristics

3.5.2.1. direction

3.5.2.2. speed

3.5.3. kinds of winds

3.5.3.1. winds coming from the east are called easterly winds

3.5.3.2. winds coming from the west are called westerly winds

3.5.3.3. planetary winds

3.5.3.3.1. winds that blow

3.5.3.4. periodic /local/ regional winds

3.5.3.4.1. winds that blow

3.5.3.4.2. examples

3.5.4. measurement of wind direction and velocity

3.5.4.1. direction of wind is found with a wind vane

3.5.4.1.1. arrow of the wind vane points to the direction of wind

3.5.4.2. velocity or speed is found with an anemometer

3.5.4.2.1. measured in km/h

3.5.4.2.2. nowadays for recording continuous wind velocity we use a anemograph

3.5.4.3. anemograph

3.5.4.3.1. records wind velocity continously

3.6. 6. clouds

3.6.1. definition

3.6.1.1. large collection of very small droplets of water or ice crystals

3.6.1.2. droplets are small and light enough to float in the air

3.6.1.3. formed though evaporation and condensation

3.6.2. classification of clouds

3.6.2.1. based on shape and height

3.6.2.1.1. high clouds

3.6.2.1.2. middle clouds

3.6.2.1.3. low clouds