Notes

Latitude & Longitude

Latitude:- Imaginary parallel lines running east and west around the globe.

Longitude:- Imaginary lines running between the poles measuring distances east and west. 

Name of the line	Degrees	Latitude or Longitude?	Description
Tropic of Cancer	23½˚ N	Latitude	Boundary of the tropical zone in the northern hemisphere
Tropic of Capricorn	23½˚ S	Latitude	Boundary of the tropical zone in the southern hemisphere
Equator	0˚	Latitude	The lines which divides the Earth into two equal halves  ( northern and southern hemisphere)
Arctic Circle	66½˚ N	Latitude	Boundary of polar region in northern hemisphere
Antarctic Circle	66½˚ S	Latitude	Boundary of polar region in southern hemisphere
Greenwich or prime meridian	0 ˚	Longitude	The line which divides the Earth into eastern and western hemisphere
International Date Line	180 ˚	Longitude	The lines which lies opposite of Greenwich meridian

Revision Question Bank

1)      What is universe?

Everything that exists everywhere is known as universe.

2)      Define galaxy?

When millions of years of stars found in a group they are called a galaxy.

3)      What is a light year? What is the speed of the light?

The distance light travels in one year. The speed of the light is 300000 km/ second.

4)      Why the stars are not seen during the day time? 

The stars are not seen during the day time because of the brightness of the sunlight.

5)      What is a solar system? 

The sun and all of the planets, moons and other bodies travelling around it is known as solar system.

6)      State the terrestrial planets and how they are composed of?

Mercury, Venus, Earth, Mars are the terrestrial planets. They are composed of rocks and metals.

7)      How is Jupiter and Saturn composed of?

They are composed mainly of hydrogen and helium.

8)      Why the sun is important to living organisms?

The sun is important because it gives us light and heat energy.

9)      State the surface temperature and the temperature at the centre of the sun?

The surface temperature is 6000˚C. The temperature at the centre is 15 million degree Celsius.

10)  Name the planets in order from the sun?

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

11)  What is gravity?

Gravity is the force of attraction which draws things together.

12)  Define latitude?

The lines drawn across the map are called latitudes.

13)  Define longitude?

The lines drawn from North Pole to South Pole are called longitudes.

14)  Describe equator?

Equator is the line which divides the Earth into two equal halves.

15)  Give a description for tropic of cancer?

The tropical zone in the northern hemisphere.

16)  Give a description for tropic of Capricorn?

The tropical zone in the southern hemisphere. 

17)  Define Arctic Circle?

The polar region in the northern hemisphere.

18)  Define Antarctic Circle?

The polar region in the southern hemisphere.

19)  Why the moon is called the satellite of the Earth?

The moon is called the satellite of the Earth because it revolves around the Earth.

20)  What is the revolution period of the moon?

The revolution period of the moon is 27 days and 8 hours.

21)  What is a leap year?

A year with 366 days is called a leap year.

22)  Define Earth’s rotation?

The movement of the Earth on its own axis is rotation.

23)  Define Earth’s revolution?

The movement of the Earth around the sun is revolution.

24)  What are the seasons that experience in the world?

Summer, winter, autumn, spring

25)  What is summer solstice?

The longest day of the year, when the sun’s direct rays reach farthest from the Equator.

26)  What is winter solstice? 

The shortest day of the year when the sun’s direct rays reach farthest from the Equator.

27)  Define equinox?

An equinox is the time of year when days and nights are equal everywhere on Earth.

28)  What is an eclipse?

When the Sun, Moon and Earth come into a straight line on the same plane, it forms an eclipse.

29)  Explain solar eclipse?

The passing of the Earth through the Moon’s shadow forms solar eclipse.

30)  Explain lunar eclipse?

The passing of the Moon through the Earth’s shadow forms lunar eclipse.

31)  Explain local mean time?

The true time of any given place is local mean time.

32)  What is GMT?

The time observed at Greenwich meridian is called GMT.

33)  How was LMT measured in the early days?

In the early days LMT was measured by the shadow cast of the sun.

34)  Why is International Date Line not straight?

To avoid the confusion of dates within one country, International Date Line is adjusted.

35)  What is atmosphere?

The air which surrounds the Earth’s surface is called atmosphere.

36)  Define lithosphere?

The land including rocks and soil is known as lithosphere.

37)  Define hydrosphere?

All the waters of the Earth are known as hydrosphere.

38)  Define biosphere?

All the varieties of life are known as biosphere.

39)  State the main gases in the air with its percentages?

Nitrogen           78%               Oxygen           21%

40)  Name the layers of the atmosphere from Earth?

Troposphere, Stratosphere, Mesosphere, Thermosphere

41)  Explain troposphere?

Troposphere contains 80% of the atmosphere’s gas all the weather we receive.

42)  Why stratosphere is important?

Stratosphere is important because ozone is present in this layer.

43)  Describe mesosphere?

Meteorites from space burn out in this layer.

44)  Explain why ozone layer is important?

Ozone layer is important because it protects us from sun’s harmful UV rays.

45)  Name any four greenhouse gases?

Carbondioxide, methane, Nitrous oxide, CFC

46)  What is greenhouse effect?

It is a natural process by which some of the radiant heat from the Sun is captured in the lower atmosphere of the Earth, maintaining the temperature of the Earth’s surface.

47)  Suggest two ways to minimize ozone depletion?

·         Reduce the emission of gases

·         Use of green products. (environment friendly)

48)  Name the layers of the Earth?

Crust, mantle, outer core, inner core

49)  Describe the layer “mantle”?

It is the largest layer of the Earth and it’s made up of molten rocks.

50)  What is a volcano?

A volcano is an opening in a planet’s crust which allows hot magma, volcanic ash and gases to escape from below the surface.

51)  Explain igneous rock? Give one example

Igneous rocks are formed when lava from volcanic eruptions cools and hardens. Eg: Granite  

52)  What is a Sedimentary rock? Give one example

Sedimentary rocks are formed when particles of sand and rock settle out of water and are then squeezed and cemented until they become solid. Eg: Limestone

53)  What are metamorphic rocks? Give one example

Metamorphic rocks are remade from other rocks when they are subjected to extreme heat and pressure. Eg: Marble

54)  Define evaporation?

When liquid water changes to gas it is called evaporation.

55)  What is condensation?

When gas changes into liquid water it is called condensation.

56)  Define transpiration?

Evaporation from the trees is called transpiration.

57)  What is precipitation?

Any moisture that falls from the sky is called precipitation.

58)  Explain water cycle?

The circulation of water above, on and below the surface of the Earth is called water cycle.

59)  Name any four forms of precipitation?

Rain, snow, hail, fog

60)  Define trench?

The deep valleys in the ocean are called trenches. 

61)  What are continents?

The large continuous land masses are called continents.

62)  What are currents?

Currents are streams of water which flows in one general direction.

63)  Explain surface water current?

Currents which flow along the surface of the oceans due to variations in temperature and winds are called surface water current.

64)  Explain deep water current?

When cold dense water travels along the bottom of the sea towards the poles, deep water currents form.

65)  What are tides?

The rise and fall of the sea water are called tides.

66)  Explain spring tide?

When the sun, moon and earth are in a straight line the tides are at their highest. They are called spring tide.

67)  Explain neap tide?

Neap tides form when the sun at right angles to the moon.

68)  What is weather?

The condition of the atmosphere at a given time and place is called weather.

69)  Define temperature?

Temperature is the degree of heat in the atmosphere.  

70)  Who are meteorologists?

The people who study weather and climate.

71)  What is the difference between local wind and planetary wind?

Local winds affect a small area. Planetary winds affect a large area.

72)  What is humidity?

The amount of water vapour in the air is called humidity.

73)  Define climate?

The usual weather condition of a place over a long period of time is climate.

74)  What are monsoon winds?

The winds that change direction with the change in season.

75)  Define nakaiy?

Nakaiy are constellation of stars.

76)  Define ocean?

The large bodies of sea water are called oceans.

77)  How is Fold Mountain formed?

When land masses bump against each other and some parts are pushed up and Fold Mountains are formed.

78)  How volcanic mountains are formed?

It is formed by lava which has erupted through the Earth’s crust.

79)  Name four countries which have sea borders?

Maldives, Indonesia, Jamaica, Srilanka

80)  What is the need of a passport?

Passport is needed to cross the borders.

81)  What is astronomy?

Astronomy is the study of universe.

82)  What is the use of a pole star?

·         To find north direction

·         To determine the latitude of a place

83)  What is Mariner’s chart?

It is a map specifically designed for navigation.

84)  Define sounding?

The depth of water noted on a mariner’s chart.

85)  What is a compass?

A compass is an instrument which shows direction.