Globe Online Test 6th Social Science Lesson 20 Questions in English

The directions on the ground are always shown with respect to the North. If we know the North, then it is easy to find the other directions, namely South, East and West.

Earth was created with a specific scale. The surface area of the Earth is 510.1 million square kilometres.

The Earth which is spherical, is flat at the poles and bulges at the Equator. The Earth cannot be compared with any other geometrical shape as it has a very unique shape. Hence, its shape is called a geoid (earth shaped).

The Earth moves around the Sun. It also rotates from the West to East on its axis at an inclination of 23 ½°.

The globe is also inclined at an angle of 23 ½°. The axis is an imaginary line. It is not actually found on the Earth.

The first globe was created by the Greeks in the year 150 AD(CE). The Earth moves around the Sun. It also rotates from the West to East on its axis at an inclination of 23 ½°.

The Indian astronomer Aryabhatta - I has mentioned in his book. ‘Aryabhatta Sidhantha’. ‘The stars in the sky seem to move towards the West because of the Earth’s roation on its axis’.

Ptolemy, a Greco – Roman mathematician, astronomer and geographer, was the first person to draw the lines of latitude and longitude on a map.

The 0° line of latitude which divides the Earth into two halves is known as the Equator. From the Equator, parallel lines are drawn towards the North and South poles at equal intervals.

From the Equator, parallel lines are drawn towards the North and South poles at equal intervals. The latitudinal extent between 1° line of latitude on Earth is 111 km.

Since the Earth is geoid shaped, the length of the lines of latitude decreases from the Equator towards the South and North Poles. The 90° North and South Poles are not found as lines, but as points.

The lines of latitude consist of 89 parallels in the Northern Hemisphere and 89 parallels in the Southern Hemisphere.

The lines of latitude consist of 89 parallels in the Northern Hemisphere and 89 parallels in the Southern Hemisphere, one at the Equator and the two poles are found as points. Totally, there are 181 parallels found on earth.

The Equator is the longest of all lines of latitude. Hence, it is also known as ‘The Great Circle’.

The area of the Earth found between the Equator (0°) and the North Pole (90°N) is called the Northern Hemisphere. The area of the Earth from the equator (0°) to the South Pole (90°S) is called the Southern Hemisphere.

0°N and S – 23½°N and S lines of latitudes are called – Low latitudes. 23½°N and S – 66½°N and S lines of latitudes are called – Middle Latitudes. 66½°N and S – 90°N and S lines of latitudes are called – High Latitudes.

The Sun’s rays do not fall equally on all parts of the earth. They fall vertically over the Equator and slanting towards the poles. Thus, all the places on earth do not have the same amount of temperature.

The region from the Equator towards the Tropic of Cancer (23½°N) and the Tropic of Capricorn (23½°S) is called the Torrid Zone. The Sun’s rays fall vertically over this region and the average temperature is very high. Hence this region is known as the Torrid Zone.

From the Tropic of Cancer (23½°N) to the Arctic Circle (66½°N) and from the Tropic of Capricorn (23½°S) to the Antarctic Circle (66½°S), the Sun’s rays fall slantingly. Moderate temperature prevails in this region. Hence, this region is called Temperate Zone.

From the Arctic Circle (66½°N) to the North Pole (900 N) and from the Antarctic Circle (66½°S) to the South Pole (90°S), the Sun’s rays fall further inclined, throughout the year. The temperature is very low. Hence, this region is known as Frigid Zone.

The imaginary lines drawn vertically connecting the North Pole and the South Pole are called lines or meridians of longitude. These lines of longitude are seen as semi circles. The 0° line of longitude is called the Prime Meridian.

There are 180 lines of longitude towards the East and West from the Prime Meridian. So, there are totally 360 lines of longitude. These lines converge at the poles. The 180° W and 180° E line of longitude are the same line.

The lines of longitude that are found between the Prime Meridian and the 180° East line of longitude are called ‘Eastern Longitudes’ and the lines of longitude that are found between the Prime Meridian (0°) and the 180° West line of longitude are called ‘Western Longitudes’. Two opposite meridians form a great circle.

The lines of longitude are found as semi circles covering 111 km at the Equator, 79 km at 45° latitude and no space between the lines at the poles.

The Royal Astronomical Observatory is located at Greenwich near London in England.

According to the International Meridian Conference held in 1884 in Washington DC in the U.S.A. all nations agreed on choosing the Greenwich Meridian as the international standard meridian (0°).

The 180° line of longitude has been fixed as the International Date Line, drawn on the Pacific Ocean between Alaska and Russia through Bering Strait.

If a person crosses International Date line from the West to East, he loses a day. On the other hand, when he crosses from the East to West, he gains a day. Based on this, the date is fixed for different countries or regions of the world.

The International Date Line is not straight. If the line is drawn straight, two places in the same country would have different dates. So, the International Date Line is found zigzag in certain places to avoid confusion.

The imaginary lines of latitude and longitude form a grid like pattern on the surface of the earth, known as the ‘Earth grid’ or ‘Geographic grid’. To locate a place exactly on earth, the latitudinal and longitudinal extensions are required.

As many as 360 lines of longitude are drawn to connect the North and South Poles around the Earth 180° on the Eastern Hemisphere and 180° on the Western Hemisphere. Time is calculated on the basis of the lines of longitude.

The Earth takes one day to rotate on its axis 360 ° = 1440 minutes So, 1 ° = 1440 360 = 4 minutes, 2 ° = 8 minutes So, in an hour (60 minutes) the earth rotates 15°

When the sun is overhead on a particular line of longitude, it is 12 noon at all the places located on that line of longitude. This is called local time. The Sun is overhead on a line of longitude only once in a day. So, the local time differs for every line of longitude.

When the Sun is overhead the Greenwich Meridian at 12 noon, it is the local time of that place. The world time is calculated by this standard line of longitude. It is known as the Greenwich Mean Time (GMT).

The word meridian is derived from the Latin word ‘Meridianus’. It means mid-day. (Medius – Middle, dies – day). So, meridian means the position of the Sun found overhead at a place at noon.

Local time is calculated when the sun is overhead at noon. Many lines of longitude may pass through a country. Countries may or may not observe a common time. The standard time of a country or a part of it is calculated keeping a particular meridian as a standard one.

The longitudinal extent of India is from 68°7’ E to 97°25’ E. As many as 29 lines of longitude pass through India.

As many as 29 lines of longitude pass through India. Having 29 standard time is not logical. Hence 82½° E line of longitude is observed as the Prime Meridian to calculate the Indian Standard Time (IST).

The 82½°E line of longitude passes through Mirzapur near Allahabad in Uttar Pradesh. This is located at an equal distance from Ghuar Mota in Gujarat and Kibithu in Arunachal Pradesh.

The world has 24 time zones. Some countries have a great longitudinal extent. So, they have more than one standard time. Example: Russia has 7 time zones

The world has 24 time zones. Some countries have a great longitudinal extent. So they have more than one standard time. Example: Russia has 7 time zones.

The Equator is the longest of all lines of latitude. Hence, it is also known as ‘The Great Circle’.

Based on the amount of heat received from the Sun, the lines of latitude help in dividing the earth into different climatic zones.

The imaginary lines of latitude and longitude form a grid like pattern on the surface of the earth, known as the ‘Earth grid’ or ‘Geographic grid’

The angle of the earth = 360 ° ; 360 ° = 360 Longitudes So 1 ° = 1440 360 = 4 minutes, In 4 minutes = 1°rotation In 60 minutes = 60 4 = 15° rotation so, in an hour (60 minutes) the earth rotates 15°