7 Science Earth, Moon, and the Sun

Science Questions and Answers
Earth, Moon and Sun

Question 1

In Fig. 12.17, how many hours of Sunlight do the North Pole and the South Pole receive during one rotation of the Earth?

Answer: During one rotation of the Earth (24 hours), both the North Pole and South Pole receive 24 hours of sunlight or 24 hours of darkness, depending on the season due to Earth's tilted axis.

Question 2 — Fill in the blanks

(i) Stars rise in the _______ and set in the _______.
(ii) Day and night are caused by the Earth's _______.
(iii) When the Moon fully covers the Sun from our view, it is called a _______ solar eclipse.

Answer: (i) Stars rise in the east and set in the west. (ii) Day and night are caused by the Earth's rotation. (iii) When the Moon fully covers the Sun from our view, it is called a total solar eclipse.

Question 3 — State whether True or False

(i) Lunar eclipse occurs when the Sun comes between the Earth and the Moon.
(ii) Sunrise happens earlier in Gujarat than in Jharkhand.
(iii) In December, the longest day occurs on the summer solstice.
(iv) We should watch the solar eclipse directly with our naked eye.
(v) Seasons occur due to the tilt of Earth's axis of rotation and its spherical shape.
(vi) The Earth's revolution around the Sun causes day and night.

Answer: (i) False - Lunar eclipse occurs when Earth comes between the Sun and Moon. (ii) False - Sunrise happens earlier in Jharkhand than in Gujarat. (iii) False - December has the shortest day, not the longest. (iv) False - Never look at solar eclipse directly as it can damage eyes. (v) True - Earth's tilted axis causes seasons. (vi) False - Earth's rotation causes day and night, not revolution.

Question 4

Padmashree saw the Orion constellation nearly overhead at 8 pm yesterday. When will she see Orion overhead today?

Answer: She will see Orion overhead at approximately 7:56 pm today. Stars appear about 4 minutes earlier each day due to Earth's movement around the Sun.

Question 5

Nandini saw a group of stars rising at midnight on 21 June. When will she see the same group of stars rising at midnight next year?

Answer: She will see the same group of stars rising at midnight on 21 June next year. The star patterns repeat after one complete year.

Question 6

Abhay noticed that when it was daytime in India, his uncle who was in the USA was generally sleeping as it was night-time there. What is the reason behind this difference?

Answer: This happens because Earth is round and rotates on its axis. When one side faces the Sun (daytime), the opposite side faces away (nighttime).

Question 7

Four friends used the following ways to see the solar eclipse. Who among them was being careless?
(i) Ravikiran used a solar eclipse goggle.
(ii) Jyothi used a mirror to project the Sun's image.
(iii) Adithya saw the Sun directly with his eyes.
(iv) Aruna attended a programme arranged by a planetarium.

Answer: Adithya was being careless. Looking at the Sun directly during an eclipse can seriously damage the eyes and cause permanent blindness.

Question 8

Fill in the circles in Fig. 12.18 appropriately with one of the following: Sun, Moon, Earth.

Answer: Solar eclipse: Positions Sun - Moon - Earth (Moon blocks sunlight from reaching Earth) Lunar eclipse: Positions Sun - Earth - Moon (Earth blocks sunlight from reaching Moon)

Question 9

The Moon is much smaller than the Sun, yet it can block the Sun completely from our view during a total solar eclipse. Why is it possible?

Answer: The Moon appears almost the same size as the Sun from Earth because it is much closer to us than the Sun, even though it's much smaller. In this manner, Moon can block the Sun completely from our view during a total solar eclipse.

Question 10

The Indian cricket team matches in Australia are often held in December. Should they pack winter or summer clothes for their trip?

Answer: They should pack summer clothes. December is summer season in Australia because it is in the Southern Hemisphere, opposite to India's winter season.

Question 11

Why do you think lunar eclipses can be seen from a large part of the Earth when they happen, but total solar eclipses can be seen from only a small part of the Earth?

Answer: During lunar eclipse, Earth's shadow covers the Moon, so anyone seeing the Moon can see the eclipse. Solar eclipse shadow is small on Earth.

Question 12

If the Earth's axis were not tilted with respect to the axis of revolution, explain what would be the effect on seasons?

Answer: There would be no seasons on Earth. Every place would have the same weather and daylight hours throughout the year because sunlight would always hit equally.