TOPIC 44 OF 46

Earth, Moon, Day & Night and Seasons

🎓 Class 6 Science CBSE Theory Ch 12 — Beyond Earth ⏱ ~14 min
🌐 Language: [gtranslate]

This MCQ module is based on: Earth, Moon, Day & Night and Seasons

[myaischool_lt_science_assessment grade_level="class_6" science_domain="earth_science" difficulty="basic"]

12.4 Earth's Two Motions — Rotation and Revolution

Our Earth is never still. It is always doing two motions at the same time:

  1. Rotation — spinning on its own axis.
  2. Revolution — going around the Sun.
Axis: An imaginary line passing through the North Pole and South Pole, about which the Earth spins. This axis is tilted by about 23.5°.

(a) Rotation — How Day and Night Happen

The Earth rotates from west to east, completing one full spin in about 24 hours. This is why we have a day and a night.

At any moment, one half of the Earth faces the Sun — that half has daytime. The other half is turned away — it has night. As the Earth keeps spinning, the sunny half slowly becomes the dark half, and vice versa.

SUN DAY NIGHT Earth
Fig 12.4 — Half of Earth facing the Sun has day; the other half has night. Earth's spin keeps switching them.

(b) Revolution — The Birth of Seasons

At the same time as spinning, the Earth also travels in a large oval path around the Sun. This journey is called a revolution. One full revolution takes 365¼ days, which we call a year.

Because Earth's axis is tilted, different parts of the Earth receive sunlight at different angles during the year. This is what causes the seasons — summer, monsoon, autumn and winter.

SUN Summer (N) Spring (N) Winter (N) Autumn (N) N = Northern Hemisphere, where India lies
Fig 12.5 — Earth's tilted axis plus its revolution around the Sun create the seasons.
Why summer is hotter: In summer, our hemisphere tilts towards the Sun. Sunlight falls more directly and the days are longer. In winter, we tilt away — sunlight spreads out and days are shorter.

12.5 The Moon — Earth's Only Natural Satellite

The Moon is our closest neighbour in space — about 3.84 lakh kilometres away. It is a cold, rocky ball, smaller than the Earth. The Moon has no air, no water and no life.

Like planets, the Moon does not make its own light. It shines because it reflects sunlight.

The Moon's Three Motions

  1. Spins on its own axis.
  2. Goes around the Earth once in about 27 days.
  3. Travels with Earth around the Sun.

Interestingly, the Moon takes the same time to spin once as it does to go around the Earth. That is why we always see the same face of the Moon from Earth!

Phases of the Moon

As the Moon goes around the Earth, we see different amounts of its sunlit side. These changing shapes are called phases of the Moon. One full cycle of phases takes about 29½ days — the basis of our Indian lunar month.

New Moon Waxing Cres. First Quarter Waxing Gibb. Full Moon Waning Gibb. Last Quarter Waning Cres.
Fig 12.6 — The eight main phases of the Moon, from New Moon to Full Moon and back again.
Amavasya (New Moon)
The Moon is between Earth and Sun; its dark side faces us. The sky is moonless.
Shukla Paksha
The lit portion grows bigger each night — called the waxing phase.
Purnima (Full Moon)
The whole face of the Moon is lit up and looks round and bright.
Krishna Paksha
The lit portion shrinks each night — called the waning phase.

12.6 Humans on the Moon

On 20 July 1969, astronaut Neil Armstrong of the USA became the first person to step on the Moon. His famous words were: "That's one small step for a man, one giant leap for mankind."

Since then, twelve people have walked on the Moon. They brought back rocks and soil that helped scientists learn how the Moon was formed.

India on the Moon: In 2023, India's Chandrayaan-3 mission landed a rover near the Moon's south pole — a place no country had landed before. We will read more about this in Part 3.

12.7 Eclipses — A Quick Look

Sometimes the Sun, Earth and Moon come in a straight line. This produces an eclipse.

Solar Eclipse (Surya Grahan)
The Moon comes between the Sun and the Earth and blocks sunlight. This can happen only on a New Moon day.
Lunar Eclipse (Chandra Grahan)
The Earth comes between the Sun and the Moon, and its shadow falls on the Moon. This can happen only on a Full Moon day.
Solar Eclipse Sun Moon Earth Lunar Eclipse Sun Earth Moon
Fig 12.7 — In a solar eclipse the Moon's shadow falls on Earth; in a lunar eclipse the Earth's shadow falls on the Moon.
Activity 12.2 — Make Your Own Day and Night

You need: a torch, a ball (a small globe if possible), a dark room.

  1. Hold the ball in one hand. Mark a small dot on it with chalk — this is "your home".
  2. In the dark room, hold the torch steady — this is the "Sun".
  3. Slowly spin the ball from left to right (west to east) while the torch points at it.
  4. Watch how your dot moves from the lit side to the dark side and back again.
Predict: Is your dot in "daytime" when it faces the torch, or when it faces away from the torch?
The dot is in daytime when it faces the torch (Sun), and in night when it faces away. The steady spin of the ball shows how day and night happen on Earth. Try spinning faster — does day become shorter or longer?

Competency-Based Questions

Arjun notices that when his mother celebrates Karva Chauth (a festival), the Moon is full and round. A fortnight later, on Diwali, the sky is dark without a Moon.

Q1. How long does the Earth take to complete one rotation on its axis? L1

  • (a) 1 hour
  • (b) 24 hours
  • (c) 7 days
  • (d) 365 days
(b) 24 hours. One full spin of the Earth gives us one day of 24 hours.

Q2. Why does the Moon change its shape from New Moon to Full Moon? L2

The Moon itself does not change shape. As it orbits the Earth, we see different parts of its sunlit side. Sometimes we see the whole lit face (Full Moon), sometimes only a sliver (Crescent), and sometimes none (New Moon).

Q3. If the Earth stopped rotating but still went around the Sun, what would happen to day and night? L5

The side of Earth facing the Sun would have continuous daytime (extremely hot), while the other side would have permanent night (freezing cold). Life as we know it would not survive on most of the planet.

Q4. Fill in the blanks: A solar eclipse happens on a ______ day, while a lunar eclipse happens on a ______ day. L1

Solar eclipse → New Moon day (Amavasya). Lunar eclipse → Full Moon day (Purnima).

Q5. True or False — Seasons happen because the Earth comes closer to the Sun in summer and moves farther in winter. Correct it if false. L4

False. Seasons are caused by the tilt of Earth's axis combined with its revolution — not by its distance from the Sun. In fact, Earth is closest to the Sun in January, which is winter in India!

Assertion – Reason

Assertion (A): Day and night keep changing on Earth.

Reason (R): The Earth rotates on its axis once every 24 hours.

  • A. Both A and R are true, R explains A.
  • B. Both true, R does not explain A.
  • C. A true, R false.
  • D. A false, R true.
Answer: A. Earth's rotation is exactly the reason we have repeating day-night cycles.

Assertion (A): We always see the same face of the Moon from Earth.

Reason (R): The Moon takes the same time to spin once on its axis as it takes to revolve around the Earth.

  • A. Both A and R are true, R explains A.
  • B. Both true, R does not explain A.
  • C. A true, R false.
  • D. A false, R true.
Answer: A. Because the Moon's day and month are equal in length, the same side always faces the Earth.

Assertion (A): A solar eclipse can happen on any day of the month.

Reason (R): The Moon moves around the Earth continuously.

  • A. Both A and R are true, R explains A.
  • B. Both true, R does not explain A.
  • C. A true, R false.
  • D. A false, R true.
Answer: D. A is false — a solar eclipse can occur only on a New Moon day, when the Moon is between the Sun and the Earth. R is true but does not make A correct.

Next → Part 3: Stars, Constellations & Indian Space Missions

Frequently Asked Questions — Earth, Moon, Day & Night and Seasons

What does the topic 'Earth, Moon, Day & Night and Seasons' cover in Class 6 Science?

The topic 'Earth, Moon, Day & Night and Seasons' is part of NCERT Class 6 Science Chapter 12 — Beyond Earth. It covers the key ideas of Earth, Moon, rotation, revolution, day and night, seasons, phases of moon, axis, tilt, explained through everyday examples, labelled diagrams and hands-on activities from the NCERT Curiosity textbook. Class 6 students learn simple definitions, see why each idea matters in daily life, and try short experiments and observations. The lesson uses easy language, colourful pictures and small questions so that young learners build a strong base for higher classes and for competency-based questions in CBSE school tests.

Why is 'Earth, Moon, Day & Night and Seasons' important for Class 6 NCERT Science?

'Earth, Moon, Day & Night and Seasons' is important because it builds the first ideas of science that Class 6 students will use again in Class 7, 8 and beyond. NCERT Chapter 12 — Beyond Earth — introduces Earth and connects it to things children already see at home, at school and in nature. Learning this topic helps students ask better questions, understand simple news about science, and score well in CBSE tests that use competency-based questions. The chapter also supports NEP 2020 by encouraging curiosity, observation and learning by doing rather than only reading and memorising.

What are the key ideas students should remember from Earth, Moon, Day & Night and Seasons?

The key ideas in 'Earth, Moon, Day & Night and Seasons' for Class 6 Science are: Earth, Moon, rotation, revolution, day and night, seasons, phases of moon, axis, tilt. Students should be able to say each term in their own words, give one or two easy examples from daily life, and draw a small labelled diagram where needed. A good way to revise is to make flashcards, write a short note in the science notebook, and solve the NCERT in-text and exercise questions of Chapter 12. Linking every idea to something seen at home or school — in the kitchen, garden, playground or sky — makes these ideas easy to remember for unit tests and the annual CBSE examination.

How is Earth, Moon, Day & Night and Seasons taught using activities in NCERT Curiosity Class 6?

NCERT Curiosity Class 6 Science teaches 'Earth, Moon, Day & Night and Seasons' through an inquiry-based approach using Predict–Observe–Explain activities. Students first make a guess, then try a small experiment with safe, easily available materials, and finally explain what happened and why. This matches the NEP 2020 focus on learning by doing. For Chapter 12 — Beyond Earth — the textbook has hands-on tasks, labelled pictures and thinking questions built for Bloom's Taxonomy Levels 1 to 6. Teachers use these activities, along with competency-based questions (CBQs) and assertion–reason items, to check real understanding instead of only rote learning.

What real-life examples of Earth can Class 6 students see at home?

Class 6 students can see Earth at home in many simple ways linked to 'Earth, Moon, Day & Night and Seasons'. Kitchens, school bags, playgrounds, the garden and the night sky are full of examples that match NCERT Chapter 12 — Beyond Earth. For example, students can look at food labels, watch changes while cooking, try safe activities with water, magnets or shadows, and observe the Sun, Moon and weather each day. Keeping a small science diary — with the date, what was observed and a quick drawing — turns daily life into a mini science lab. These real-life links make concepts easy to remember and help in answering competency-based questions in CBSE Class 6 Science.

How does 'Earth, Moon, Day & Night and Seasons' connect to other chapters of Class 6 Science?

'Earth, Moon, Day & Night and Seasons' connects to many other chapters in NCERT Class 6 Science Curiosity. The ideas of Earth come back when students study related topics like diversity in the living world, food, magnets, measurement, materials, temperature, water, separation, habitats, natural resources and the solar system. For example, what students learn here helps them build mental pictures for later chapters and for Class 7 and Class 8 Science. Teachers often ask cross-chapter questions in CBSE exams to check if students can use what they learned in Chapter 12 — Beyond Earth — in new situations. This linked approach matches the NEP 2020 and NCF 2023 focus on holistic, competency-based learning.

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