G6 Social Science Rotation and Revolution PDF

O NEW HORIZON SCHOLARS SCHOOL Kavesar, Ghodbunder Road, Thane (W)-400615 CBSE Affiliation No: 1130470 Grade: VI: Subject: Social Science: Geography 2024-25 Name:...

O NEW HORIZON SCHOLARS SCHOOL Kavesar, Ghodbunder Road, Thane (W)-400615 CBSE Affiliation No: 1130470 Grade: VI: Subject: Social Science: Geography 2024-25 Name: Date: / _/ Roll No: Div: Rotation and Revolution Key Words (a) Dusk (e)Illumination (b) Spin (f) Axial (c) Dawn (g) Perpendicular (d) Equinox (h) Equatorial (e)Solstice (i) Illustration A Fill in the blanks. 1. At noon the Sun's rays are directly overhead. 2. Day and night are caused by the rotation of the earth. 3. The Earth spins about its axis. 4. One revolution of the Earth takes 365 1/4 days, or one year. 5. Equatorial regions have almost equal days and equal nights throughout the year. B Choose the correct option. 1. At this time in the day, the Sun is overhead. Noon 2. These latitudes experience the overhead Sun. Tropic of Cancer, Tropic of Capricorn and Equator 3. This season is neither hot nor cold. Spring 4. This is the season which comes before winter. Autumn 5. A leap year has: 366 days C Answer the following questions very briefly. TB (1) During which time of the year are nights and days equal? Pgno.138 Ans 1. During an equinox, days and nights are equal all over the Earth. 2. Equinoxes occur twice a year, generally around March 20 and September 22. (2) What is the Earth's imaginary path around the Sun called? Ans Orbit (3) What is the period of dim light before Sunrise called? Ans Dawn (4) When do we experience the longest day of the year in the Northern Hemisphere? Ans Summer solstice, 21st June is the longest day in the Northen Hemisphere. Pg no 138  (5) What is mid-day? Ans When the Sun is overhead at a particular place it is mid-day in that place. D Answer the following questions briefly (1) What would happen if the Earth's axis was not tilted? NP Ans 1. If the axis of the Earth was not tilted to the plain of its orbit all parts of the globe would have experienced equal length of day and night throughout the year. 2. If the earth's axis had not been tilted to the plane of its orbit then there would have been no seasons and humanity would have suffered. (2) What is the line of illumination? TB PgNo136 Ans The line of illumination separates the day from the night. (3) What is meant by an overhead Sun? TB Pg No 138 Ans When the rays of the Sun are perpendicular at a place on the Earth we say that the Sun is overhead. (4) Which movement of the Earth causes seasons? NP Ans Revolution causes seasons. (5) What causes variation in the length of days and nights? NP Ans Effects of revolution and the tilt of Earth's axis cause variation in the length of days and nights. E Answer the following questions in detail. (1) What are the effects of the Earth's rotation? NP Ans 1. Rotation of the Earth causes day and night. 2. It also causes intervening periods of dawn and dusk. 3. The Earth’s rotation on its tilted axis causes the Sun’s rays to fall at different angles on its surface. 4. The anti-clockwise direction of the rotation causes the Sun to rise in the east and set in the west. 5. It gives the Earth a geoid shape. (2) How are seasons caused? NP Ans 1. The seasons are caused by the Earth’s revolution and the tilt of its axis of 231/2 degree. 2. As it revolves around the Sun, the portion leaning towards it keeps changing as it moves on its imaginary path. 3. When the Northern Hemisphere leans towards the Sun it receives more light and heat, making it warmer. 4. The same time the Southern Hemisphere which is tilted away from the Sun gets a lesser amount of heat and light making it colder. 5. Seasons change with the change in the position of the Earth around the Sun. 6. A year is divided into four seasons - Spring, Summer, Autumn and Winter. - From June to August, it is summer in the Northern Hemisphere and winter in the Southern Hemisphere. (3) What do we understand by solstices? TB PgNo138. Ans 1. The term 'solstice' originates from two Latin words, sol which means Sun, and sistere which means to stand still. 2. The summer solstice occurs around June 21 in the Northern Hemisphere and marks the longest day of the year. 3. On this day, the Sun is overhead at the Tropic of Cancer. On the same day, the southern hemisphere experiences winter solstice, marking the shortest day of the year. 4. Six months later, on December 22, the Sun is overhead at the Tropic of Capricorn. On  the same day, the Southern Hemisphere experiences summer solstice. (4) What are equinoxes? TB Pg No138 Ans 1. The term equinox is derived from the Latin word ‘aequus’ which means equal and ‘nox’, meaning night. 2. An equinox occurs when the Sun is overhead at the Equator. At this position, neither of the poles is tilted towards the sun. 3. When an equinox occurs days and nights are equal all over the Earth. 4.Equinoxes occur twice a year, generally around March 20 and September 22. 5. The vernal equinox occurs around March 21 in the Northern Hemisphere. This marks the beginning of spring. 6. On the day of the spring equinox in the Northern Hemisphere the Southern Hemisphere experiences autumn equinox around September 23. (5) Why does the Southern Hemisphere have summer in December? NP Ans 1. As the Earth travels around the Sun on its imaginary path, the side leaning towards it keeps changing. 2. In December, the Southern Hemisphere leans towards the Sun and receives more light and heat, making it warmer. 3. The result of this is that the Southern Hemisphere enjoys summer in December. WORK- BOOK Rotation and Revolution A. Choose the correct option 1. a 2. d 3. b 4. c 5. b B. Write true or False. 1. True 2. False 3. False 4. True 5. True C. Fill in the blanks 1. day. 2. axis 3. revolution. 4. Cancer 5. winter D. Write these words in correct column Rotation – day, night, axis Revolution – orbit, year, seasons  E. read the clues and write the correct answer 1. Sun 2. Rotation 3 February 4.Summer 5.Equator F. Write very short answers 1. Rotation and revolution are the two motions of the Earth. 2. The plane formed by the orbit is known as the orbital plane. 3. There are 29 days in February in a leap year. 4. The Tropic of Capricorn receives the direct rays of the Sun on 22 December every year. 5. The Southern Hemisphere enjoys spring season on 23 September. G. Write very short answers 1. The circle that divides the day from night on the globe is called the circle of illumination. (Repeated Q. refer TBQ) 2. Seasons change due to the revolution of the Earth and the inclination of the Earth’s axis in a fixed direction. (Repeated Q. refer TBQ) 3. (i)Due to the spherical shape of the Earth, only one half of it gets light from the Sun at a time. (ii)The portion facing the Sun experiences day while the other half away from the Sun experiences night. (iii) Thus half of the Earth experiences day and night at a time. (Repeated Qrefer TBQ) 4.(i)On 22 December, the Tropic of Capricorn receives direct rays of the Sun as the South Poletilts towards it. (ii)As the Sun’s rays fall vertically at the Tropic of Capricorn, so the areas near the Tropic of Capricorn receive more light on this day. 5.(i)When the whole Earth experiences equal days and equal nights, it is called an equinox. (ii) We experience the equinoxes on 21 March and 23 September every year. (Repeated Q refer TBQ) H. Write the long answers. 1. (i)The movement of the Earth on its axis is called rotation, while the movement of the Earth around the Sun in its fixed path or orbit is called revolution. (ii) The Earth takes about 24 hours to complete one rotation and this period of rotation is known as the earth day. (iii)On the other hand, the Earth takes 365¼ days to complete one revolution and this period of revolution is known as a year.. 2. (i)If the Earth did not rotate, the portion of the Earth facing the Sun would always experience day, thus bringing continuous warmth to the region. (ii) The other half would remain in darkness and be freezing cold all the time. (iii) Life would not have been possible in such extreme conditions 3. (i)The Earth takes 365¼ days to revolve around the Sun. (ii)We consider a year as consisting of 365days only and ignore six hours for the sake of convenience. (iii) Six hours saved every year are addedto make one day (24 hours) over a span of four years. (iv)Thus we have a leap year after every four years. 4. (i)Places near the poles experience six months of continuous day and six months of continuous night due to the inclination of the Earth’s axis in a fixed direction. (ii) When the North Pole is inclined towards the Sun for about six months, the places beyond the Arctic Circle experience continuous daylight. (iii) During the same time, the South Pole is tilted away from the Sun and the places beyondthe Antarctic Circle experience continuous night. 5. (i)On 21 June, the Northern Hemisphere is tilted towards the Sun. The rays of the Sun fall directlyon the Tropic of Cancer. (ii) As a result, these areas receive more heat and light. (iii)Thus it is summer inthe Northern Hemisphere. (iv) At this time, all these conditions are reversed in the Southern Hemisphere so it is winter in the Southern Hemisphere.(v) On 22 December, the Southern Hemisphere is tilted towards the Sun.(vi) The rays of the Sun fall directly on the Tropic of Capricorn. As a result, these areas receive more heat and light. (vii)Thus it is summer in the Southern Hemisphere. (viii) At this time, all these conditions are reversed in the Northern Hemisphere so it is winter in the Northern Hemisphere.