Keywords To Remember
- Rotation
The spinning of the Earth on its axis from west to east, which takes about 24 hours to complete one full turn. - Revolution
The movement of the Earth around the Sun in an elliptical orbit, taking approximately 365¼ days to complete one full orbit. - Axis
An imaginary line passing through the North and South Poles around which the Earth rotates. - Inclination (Tilt of the Axis)
The angle (23½°) that Earth’s axis makes with the perpendicular to the plane of its orbit around the Sun. - Orbit
The curved path followed by the Earth as it revolves around the Sun. - Day
The period during which a particular part of the Earth faces the Sun and experiences sunlight. - Night
The period during which a particular part of the Earth is turned away from the Sun and remains in darkness. - Dawn
The time just before sunrise when the sky begins to lighten but the Sun is not yet visible. - Sunrise
The moment when the upper edge of the Sun appears above the horizon in the morning. - Noon
The time of day when the Sun is at its highest point in the sky for a particular location. - Sunset
The moment when the upper edge of the Sun disappears below the horizon in the evening. - Dusk
The time just after sunset when the sky is partially illuminated but the Sun is below the horizon. - Leap Year
A year having 366 days, occurring every four years, to account for the extra 6 hours per year accumulated during Earth’s revolution. - Elliptical Orbit
The slightly oval-shaped path that the Earth follows around the Sun. - Perihelion
The point in Earth’s orbit when it is closest to the Sun (around January 4th). - Aphelion
The point in Earth’s orbit when it is farthest from the Sun (around July 4th). - Solstice
The two times in a year when the Sun’s rays fall directly on the Tropic of Cancer (summer solstice) or Tropic of Capricorn (winter solstice), marking the longest and shortest days. - Equinox
The two times in a year when the Sun’s rays fall directly on the Equator, resulting in equal day and night durations worldwide. - Summer Solstice
Occurs around June 21st when the Northern Hemisphere is tilted towards the Sun, resulting in the longest day of the year there. - Winter Solstice
Occurs around December 22nd when the Northern Hemisphere is tilted away from the Sun, resulting in the shortest day of the year there. - Vernal Equinox
Occurs around March 21st when the Sun is directly above the Equator, marking the start of spring in the Northern Hemisphere. - Autumnal Equinox
Occurs around September 23rd when the Sun is directly above the Equator, marking the start of autumn in the Northern Hemisphere. - Tropic of Cancer
A line of latitude at 23½° North, where the Sun’s rays are vertical during the summer solstice in the Northern Hemisphere. - Tropic of Capricorn
A line of latitude at 23½° South, where the Sun’s rays are vertical during the summer solstice in the Southern Hemisphere. - Arctic Circle
A line of latitude at approximately 66½° North, marking the boundary of the area where the Sun can remain continuously above or below the horizon for 24 hours. - Antarctic Circle
A line of latitude at approximately 66½° South, marking the boundary of the area where there can be continuous daylight or darkness for 24 hours. - Solar Day
The time taken for the Earth to rotate once relative to the Sun, approximately 24 hours. - Sidereal Day
The time taken for the Earth to complete one rotation relative to distant stars, about 23 hours 56 minutes. - Heat Zone
Regions on Earth classified by their climate based on latitude, such as Torrid Zone, Temperate Zone, and Frigid Zone. - Day Length Variation
Changes in the duration of daylight hours throughout the year due to Earth’s tilt and revolution. - Season
A division of the year marked by changes in weather, temperature, and daylight hours caused by Earth’s revolution and tilt. - Equator
The imaginary line around the middle of the Earth at 0° latitude, dividing Earth into Northern and Southern Hemispheres.
Something To Know
A. Tick (✔ ) the correct option.
- On 22nd December, the sun rays are vertical at the ̶
(a) Tropic of Cancer
(b) Tropic of Capricorn
(c) Equator
(d) Arctic Circle
Answer – (b) Tropic of Capricorn
- Which statement about a leap year is incorrect?
(a) it has 366 days in a year.
(b) one extra day is added in February.
(c) February has 28 days.
(d) it comes in every fourth year.
Answer – (c) February has 28 days.
- If there is noon on one side of the earth, the opposite side will have-̶
(a) morning
(c) mid-night
(b) evening
(d) twilight
Answer – (c) mid-night
- On 23rd September, mid-day sun is overhead at the ̶
(a) Equator
(b) Tropic of Cancer
(c) Tropic of Capricorn
(d) Antarctic Circle
Answer – (a) Equator
- The angle of sun rays on 21st June on the Tropic of Cancer is ̶
(a) 66½°
(b) 90°
(c) 23½°
(d) 50°
Answer – (b) 90°
B. Fill in the blanks.
- The earth revolves around the sun in a fixed path called as ___________________ .
Answer – orbit
- The angle of inclination of the earth’s axis is ___________________ with its orbital plane.
Answer – 23½°
- Two motions of the earth are ___________________ and ___________________ .
Answer – rotation, revolution.
- The time of sunrise is called ___________________ .
Answer – dawn
- The earth completes one revolution around the sun in ___________________ days and ___________________ hours.
Answer – 365 days and 6
C. Match the following:
- The duration of the day and night is equal in both the hemispheres on – (a) southern hemisphere
- The arctic circle has six-month long days in (b) on 21st June and 22nd December respectively
- The Tropic of Capricorn is located in (c) summer solstice
- The rays of the sun are vertical on Tropic of Cancer and Tropic of Capricorn (d) vernal equinox
- Spring equinox is also called (e) 23rd September and 21st March
Answer –
Column A
Column B
1. The duration of the day and night is equal in both the hemispheres on
(e) 23rd September and 21st March
2. The arctic circle has six-month long days in
(b) on 21st June and 22nd December respectively
3. The Tropic of Capricorn is located in
(a) southern hemisphere
4. The rays of the sun are vertical on Tropic of Cancer and Tropic of Capricorn
(c) summer solstice
5. Spring equinox is also called
(d) vernal equinox
D. Answer the following questions in brief.
- What is rotation? How much time does earth take in completing one rotation?
Answer – Rotation is the spinning of the Earth on its axis from west to east. The Earth takes about 24 hours to complete one full rotation.
- What is meant by the revolution of the earth?
Answer – Revolution is the movement of the Earth around the Sun in a fixed elliptical orbit, which takes about 365¼ days to complete one revolution.
- What is a leap year?
Answer – A leap year is a year with 366 days instead of 365. One extra day is added to February (29 days) every four years to account for the extra 6 hours each year.
- What is an equinox? Which seasons are indicated by it in both the hemispheres?
Answer – An equinox is the time when the Sun is directly overhead at the Equator, making day and night equal. It marks spring (vernal equinox) in the Northern Hemisphere and autumn (autumnal equinox) in the Southern Hemisphere, and vice versa.
- Why does the duration of day and night change in a year?
Answer – The duration changes due to the tilt (inclination) of the Earth’s axis and its revolution around the Sun, causing varying angles of sunlight and length of days in different seasons.
E. Answer the following questions.
- Why are days and nights equal on 21st March at all places on the earth? Explain.
Answer – On 21st March, the Sun’s rays fall directly on the Equator, so both the Northern and Southern Hemispheres receive equal sunlight. This causes day and night to be equal, lasting about 12 hours each everywhere.
- Explain with the help of a diagram, why seasons are reversed between Northern and Southern Hemispheres.
Answer – When the Northern Hemisphere tilts toward the Sun, it experiences summer while the Southern Hemisphere tilts away and experiences winter. After six months, the tilt reverses causing opposite seasons. (Diagram needed in notebook)
- Why does the month of February have 29 days, after every four years? Explain.
Answer – Because the Earth takes 365¼ days to orbit the Sun, the extra ¼ day accumulates each year. After four years, these add up to one full day, which is added to February making it 29 days, called a leap year.
- How do day and night occur on the earth? Explain with the help of a diagram.
Answer – Day and night occur due to the Earth’s rotation on its axis. The side facing the Sun experiences day, while the opposite side is in darkness and experiences night. As Earth rotates, places move between day and night. (Diagram needed in notebook)
Value Based Question
The planet earth while rotating is also revolving around the sun in an elliptical orbit in a year.
- What would happen if it stops moving?
Answer – If Earth stops rotating and revolving, there would be no day and night or seasons, drastically affecting life, climate, and survival.
- Why is this movement considered essential for our survival on the planet?
Answer – Rotation causes day and night, regulating temperature and life cycles, while revolution causes seasons that affect climate and food production, making life possible on Earth.
Something To Do
- Find out the duration of day and night at the place where you live on the following days with the help of sunrise and sunset timings.
(a) 21st March
Answer – About 12 hours day and 12 hours night
(b) 21st June
Answer – Longer days and shorter nights (summer)
(c) 23rd September
Answer – About 12 hours day and 12 hours night
(d) 22nd December
Answer – Shorter days and longer nights (winter)
- Make a chart to be displayed in your classroom showing the revolution of the earth and the seasons.
Answer – Do it yourself
- Try the experiment showing formation of day and night with the help of a lamp and a globe at home. Write your observations and then discuss in the class.
Answer – Do it yourself
Additional Questions And Answers – 01
Fill in the Blanks (with Answers)
- The Earth completes one rotation in __________ hours.
Answer: 24 - The imaginary line around which the Earth spins is called its __________.
Answer: axis - The Earth’s axis is tilted at an angle of __________ degrees.
Answer: 23½° - The path followed by the Earth around the Sun is called its __________.
Answer: orbit - The time when the sun is directly overhead at the Equator and day and night are equal is called __________.
Answer: equinox - The point on Earth’s surface directly under the Sun’s rays at noon is called the __________.
Answer: subsolar point - The longest day in the Northern Hemisphere occurs on __________.
Answer: 21st June - A year with 366 days is called a __________ year.
Answer: leap - The Earth revolves around the Sun in approximately __________ days.
Answer: 365¼ - The dark part of the Earth during rotation experiences __________.
Answer: night
Multiple Choice Questions (with Answers)
- What causes day and night on Earth?
(a) Revolution
(b) Rotation ✔
(c) Orbit
(d) Axis tilt - Which hemisphere experiences summer during the December solstice?
(a) Northern
(b) Southern ✔
(c) Both
(d) Neither - How long does it take Earth to complete one revolution around the Sun?
(a) 24 hours
(b) 365 days
(c) 365¼ days ✔
(d) 1 month - What is the angle between Earth’s axis and its orbital plane?
(a) 90°
(b) 66½° ✔
(c) 23½°
(d) 45° - On which date are day and night equal worldwide?
(a) 21st June
(b) 23rd September ✔
(c) 22nd December
(d) 21st March - During which event do both hemispheres receive equal sunlight?
(a) Summer solstice
(b) Winter solstice
(c) Equinox ✔
(d) Leap year - Which of the following is NOT true about leap years?
(a) Occurs every 4 years
(b) February has 29 days
(c) It adds one hour to the year ✔
(d) Year has 366 days - What happens to the Northern Hemisphere during the summer solstice?
(a) It tilts away from the Sun
(b) It tilts towards the Sun ✔
(c) It experiences equal day and night
(d) It experiences winter - The region around the North Pole has sunlight for about how many months during summer?
(a) 3 months
(b) 6 months ✔
(c) 9 months
(d) 12 months - What is dawn?
(a) The time after sunrise
(b) The time before sunrise ✔
(c) The time at noon
(d) The time at sunset
True/False Questions (with Answers)
- The Earth rotates from east to west.
Answer: False (It rotates from west to east) - The Earth’s axis is perpendicular to its orbital plane.
Answer: False (It is tilted at 23½°) - The Earth completes one revolution in about 365 days.
Answer: True - Day and night are caused due to the Earth’s revolution.
Answer: False (They are caused due to rotation) - The Southern Hemisphere experiences winter during the Northern Hemisphere’s summer solstice.
Answer: True - Leap year happens every three years.
Answer: False (It happens every four years) - The length of day and night is always equal all over the Earth.
Answer: False (It varies except during equinox) - The sun rays fall vertically on the Tropic of Cancer during summer solstice.
Answer: True - The Arctic Circle faces 24 hours of darkness during the winter solstice.
Answer: True - The Earth’s revolution is responsible for the changing seasons.
Answer: True
Short Questions (with Answers)
- What is the difference between rotation and revolution?
Answer: Rotation is the spinning of the Earth on its axis; revolution is the Earth’s movement around the Sun. - Why do we have leap years?
Answer: Because Earth takes 365¼ days to revolve around the Sun, the extra ¼ day accumulates and is added every four years as a leap day. - What causes the seasons to change?
Answer: The tilt of the Earth’s axis and its revolution around the Sun cause changing seasons. - When do day and night have equal length?
Answer: During the equinoxes, on 21st March and 23rd September. - What is the significance of the Tropic of Capricorn?
Answer: It is the latitude where the sun is directly overhead during the December solstice.
Competency Based Questions (Reasoning & Assertion)
- Assertion: The Earth’s axis is tilted at 23½°.
Reason: This tilt causes the changing seasons.
(a) Both assertion and reason are correct, and reason explains assertion.
(b) Both are correct, but reason does not explain assertion.
(c) Assertion is correct, but reason is wrong.
(d) Both are wrong.
Answer: (a) - Assertion: Day and night occur because Earth revolves around the Sun.
Reason: One half of Earth faces the Sun and has day while the other half has night.
Answer: (c) Assertion is wrong, reason is correct. - Assertion: Leap year has 366 days.
Reason: Earth completes a revolution in exactly 365 days.
Answer: (c) Assertion is correct, reason is wrong. - Assertion: During the summer solstice, the Northern Hemisphere receives more sunlight.
Reason: The Northern Hemisphere is tilted towards the Sun.
Answer: (a) Both correct, reason explains assertion. - Assertion: The Earth’s axis is perpendicular to the orbital plane.
Reason: This causes equal day and night throughout the year.
Answer: (d) Both wrong.
High Order Thinking Skill Questions (HOTS)
- How would life on Earth change if the Earth’s axis was not tilted?
Answer: Without the tilt, there would be no seasons; temperature and weather patterns would be uniform year-round. - Explain why the Arctic Circle experiences 24 hours of daylight in summer but 24 hours of darkness in winter.
Answer: Due to Earth’s tilt, during summer solstice the Arctic Circle is tilted towards the Sun, so it receives continuous sunlight. During winter solstice, it tilts away causing darkness. - How does the elliptical shape of Earth’s orbit affect the seasons?
Answer: The elliptical orbit causes slight variations in distance from the Sun, but seasons are primarily caused by the tilt of the axis rather than this distance. - If the Earth’s rotation slowed down, how would that impact day and night?
Answer: Days and nights would become longer, affecting climate, life cycles, and biological rhythms. - Why is the leap year necessary despite the fact that it occurs only once every four years?
Answer: To compensate for the extra 0.25 days each year and keep the calendar aligned with Earth’s position in orbit.
Long Questions (40-50 words)
- Explain the cause of day and night on Earth.
Answer: Day and night are caused by Earth’s rotation on its axis. The side facing the Sun experiences daylight, while the opposite side experiences darkness. This rotation takes 24 hours, causing a cycle of day and night. - Describe why seasons occur on Earth.
Answer: Seasons occur due to Earth’s tilted axis and its revolution around the Sun. When a hemisphere tilts towards the Sun, it experiences summer with longer days. When it tilts away, it experiences winter with shorter days. - What is a leap year, and why is it needed?
Answer: A leap year has 366 days and occurs every four years. It is needed because Earth takes 365¼ days to orbit the Sun, and the extra ¼ day accumulates, requiring an extra day every four years to keep the calendar accurate. - Explain the significance of equinoxes.
Answer: Equinoxes occur twice a year when the Sun is directly overhead at the Equator, causing equal day and night worldwide. They mark the beginning of spring and autumn seasons in different hemispheres. - How do the day lengths change during solstices?
Answer: During solstices, one hemisphere experiences its longest day and shortest night (summer solstice), while the other experiences its shortest day and longest night (winter solstice) due to Earth’s axis tilt.
Additional Questions And Answers – 02
Fill in the Blanks Questions and Answers
- The Earth’s motion on its axis is called __________.
Answer: Rotation - The Earth completes one revolution around the sun in __________ days.
Answer: 365¼ - The Earth’s axis is tilted at an angle of __________° from the vertical.
Answer: 23½ - The position on 21st June is called __________ solstice in the Northern Hemisphere.
Answer: Summer - The sun’s rays are vertical at the __________ on 23rd September.
Answer: Equator - A year with 366 days is called a __________ year.
Answer: Leap - The minimum distance between the Earth and the sun occurs on __________ January.
Answer: 4th - The __________ Circle experiences 24 hours of sunlight on 21st June.
Answer: Arctic - The position on 21st March is called __________ equinox in the Northern Hemisphere.
Answer: Vernal - The Earth’s fixed path around the sun is called its __________.
Answer: Orbit - The __________ Hemisphere has winter on 22nd December.
Answer: Northern - The sun’s rays are vertical at the __________ on 22nd December.
Answer: Tropic of Capricorn - The Earth’s rotation causes __________ and night.
Answer: Day - The __________ solstice occurs in the Southern Hemisphere on 22nd December.
Answer: Summer - The Earth’s axis makes an angle of __________° with its orbital plane.
Answer: 66½
Multiple Choice Questions (MCQs) and Answers
- What is the Earth’s motion around the sun called?
a) Rotation
b) Revolution
c) Inclination
d) Orbit
Answer: b) Revolution - How long does it take for the Earth to complete one rotation?
a) 12 hours
b) 24 hours
c) 365 days
d) 6 hours
Answer: b) 24 hours - What causes day and night on Earth?
a) Revolution
b) Rotation
c) Tilt of the axis
d) Orbit
Answer: b) Rotation - On which date is the summer solstice in the Northern Hemisphere?
a) 23rd September
b) 21st June
c) 22nd December
d) 21st March
Answer: b) 21st June - What is the tilt angle of the Earth’s axis from the vertical?
a) 66½°
b) 23½°
c) 90°
d) 45°
Answer: b) 23½° - When are days and nights equal in both hemispheres?
a) 21st June
b) 22nd December
c) 23rd September
d) 4th January
Answer: c) 23rd September - What is the maximum distance between the Earth and the sun?
a) 147.5 million km
b) 152.6 million km
c) 100 million km
d) 200 million km
Answer: b) 152.6 million km - Which region experiences six months of sunlight starting on 21st March?
a) South Pole
b) Equator
c) North Pole
d) Tropic of Cancer
Answer: c) North Pole - What is the season in the Southern Hemisphere on 21st March?
a) Summer
b) Winter
c) Autumn
d) Spring
Answer: c) Autumn - What is added to February every four years to account for a leap year?
a) One day
b) Two days
c) Six hours
d) One week
Answer: a) One day
True/False Questions and Answers
- The Earth’s rotation causes day and night.
Answer: True - The Earth completes one revolution in 365 days exactly.
Answer: False (It takes 365¼ days.) - The Northern Hemisphere has winter on 21st June.
Answer: False (It has summer.) - A leap year has 366 days.
Answer: True - The Earth’s axis is perpendicular to its orbital plane.
Answer: False (It is tilted at 66½°.) - Days and nights are equal on 23rd September globally.
Answer: True - The sun’s rays are vertical at the Equator on 22nd December.
Answer: False (They are vertical at the Tropic of Capricorn.) - The Arctic Circle experiences 24 hours of darkness on 21st June.
Answer: False (It has 24 hours of sunlight.) - The Southern Hemisphere has spring on 23rd September.
Answer: True - The Earth’s orbit around the sun is circular.
Answer: False (It is elliptical.)
Short Questions and Answers
- What is the Earth’s rotation?
Answer: Rotation is the Earth’s spinning on its axis from west to east, completing one round in about 24 hours. - What causes day and night?
Answer: The Earth’s rotation causes day and night, as the lighted half facing the sun has day, and the other half has night. - What is a leap year?
Answer: A leap year has 366 days, with an extra day added to February every four years to account for 365¼-day revolutions. - What is the inclination of the Earth’s axis?
Answer: The Earth’s axis is tilted at 23½° from the vertical or 66½° with its orbital plane. - What is summer solstice?
Answer: Summer solstice occurs when a hemisphere is tilted toward the sun, receiving longer days and more heat, like on 21st June in the Northern Hemisphere. - What is an equinox?
Answer: An equinox occurs when the sun’s rays are vertical over the Equator, making days and nights equal, like on 23rd September. - When is the Earth closest to the sun?
Answer: The Earth is closest to the sun, at 147.5 million km, on 4th January. - What is winter solstice?
Answer: Winter solstice occurs when a hemisphere is tilted away from the sun, receiving shorter days, like on 22nd December in the Northern Hemisphere. - What is the Earth’s revolution?
Answer: Revolution is the Earth’s movement around the sun in an elliptical orbit, taking 365¼ days to complete one cycle. - Why do seasons occur?
Answer: Seasons occur due to the Earth’s tilted axis and revolution, causing varying angles and duration of sunlight in each hemisphere.
Competency-Based Questions and Answers (Reasoning and Assertion)
- Assertion: The Earth’s rotation causes day and night.
Reason: As the Earth spins from west to east, one half faces the sun, experiencing day, while the other half is in darkness.
Answer: Both assertion and reason are true, and the reason explains the assertion. - Assertion: Days and nights are equal on 23rd September.
Reason: The sun’s rays are vertical over the Equator, providing equal sunlight to both hemispheres.
Answer: Both assertion and reason are true, and the reason explains the assertion. - Assertion: The Northern Hemisphere has summer on 21st June.
Reason: The Northern Hemisphere is tilted toward the sun, receiving more direct rays and longer days.
Answer: Both assertion and reason are true, and the reason explains the assertion. - Assertion: A leap year occurs every four years.
Reason: The Earth takes 365¼ days to revolve around the sun, and the extra hours are added to February.
Answer: Both assertion and reason are true, and the reason explains the assertion. - Assertion: The Southern Hemisphere has winter on 21st June.
Reason: The Southern Hemisphere is tilted away from the sun, receiving slanting rays and shorter days.
Answer: Both assertion and reason are true, and the reason explains the assertion.
High Order Thinking Skill (HOTS) Questions and Answers
- Why does the length of day and night vary during the year?
Answer: The Earth’s tilted axis causes varying day and night lengths as it revolves around the sun. When a hemisphere tilts toward the sun, it gets longer days; when tilted away, days shorten, creating seasonal variations. - How does the Earth’s elliptical orbit affect its distance from the sun?
Answer: The Earth’s elliptical orbit causes distance variations, with the closest point (147.5 million km) on 4th January and farthest (152.6 million km) on 4th July, influencing seasonal intensity but less significantly than the axis tilt. - Why do equinoxes result in equal day and night globally?
Answer: During equinoxes, on 21st March and 23rd September, the sun’s rays are vertical over the Equator, evenly illuminating both hemispheres. This balances sunlight distribution, making day and night each 12 hours worldwide. - How does the tilt of the Earth’s axis contribute to seasonal changes?
Answer: The 23½° tilt of the Earth’s axis causes different angles of sunlight during revolution. When a hemisphere tilts toward the sun, it receives direct rays and longer days, causing summer; when tilted away, it gets slanting rays, causing winter. - Why does the Arctic Circle experience 24 hours of sunlight on 21st June?
Answer: On 21st June, the Northern Hemisphere is tilted toward the sun, and the Arctic Circle (66½° N) is fully exposed to sunlight due to the Earth’s tilt, receiving 24 hours of daylight during the summer solstice.
Long Questions and Answers (40-50 Words)
- Explain how the Earth’s rotation causes day and night.
Answer: The Earth’s rotation from west to east exposes each part to sunlight sequentially. The half facing the sun experiences day, while the opposite half is in darkness, causing night. This cycle repeats every 24 hours, creating alternating day and night. - Describe the significance of the Earth’s revolution.
Answer: The Earth’s revolution around the sun in 365¼ days causes seasonal changes due to its tilted axis. It determines the cycle of seasons, influences climate, and necessitates leap years to align the calendar with the solar year. - How does the summer solstice occur in the Northern Hemisphere?
Answer: On 21st June, the Northern Hemisphere tilts toward the sun, receiving vertical rays at the Tropic of Cancer. Longer days and more heat result in summer, with the Arctic Circle experiencing 24 hours of sunlight, called summer solstice. - What is an equinox, and when does it occur?
Answer: An equinox occurs when the sun’s rays are vertical over the Equator, causing equal 12-hour days and nights globally. It happens on 21st March (vernal equinox in the Northern Hemisphere) and 23rd September (autumnal equinox). - Why is a leap year necessary?
Answer: The Earth takes 365¼ days to revolve around the sun. To align the calendar, an extra day is added to February every four years, creating a leap year with 366 days, ensuring seasonal and calendar accuracy.