Aarav from Chandigarh called his cousin Nisha in New Zealand one evening. "It is 7 PM here and already dark," said Aarav. "That is strange," replied Nisha, "because here it is morning and the Sun is shining brightly!"
Aarav was puzzled. How can it be night in India and daytime in New Zealand at the same time? The answer lies in how our Earth moves. Let us find out.
Shape of the Earth
Long ago, people thought the Earth was flat. But today we know that the Earth is shaped like a ball -- it is roughly a sphere. Scientists call its exact shape a geoid, which means it is slightly flattened at the top (North Pole) and bottom (South Pole) and slightly bulging at the middle (Equator). Think of it as a ball that has been gently pressed from the top and bottom.
When astronauts from ISRO (Indian Space Research Organisation) and NASA look at the Earth from space, they see a beautiful blue and green sphere.
The Earth's Axis
Imagine a thin rod passing through the Earth from the North Pole to the South Pole. This imaginary line is called the axis. The Earth spins around this axis, just like a spinning top. The axis is not straight up and down -- it is tilted at an angle of about 23.5 degrees. This tilt is very important because it causes the seasons.
Rotation -- Spinning on Its Axis
The Earth spins (rotates) on its axis from west to east. It takes approximately 24 hours (one full day and night) to complete one rotation.
How rotation causes day and night: The Sun lights up only one half of the Earth at a time. The half facing the Sun has daytime. The half facing away from the Sun has nighttime. As the Earth keeps spinning, different parts of the Earth move into sunlight and then into darkness. This is why we have day and night.
This is also why when it is night in India, it is daytime in countries like the United States and Brazil, which are on the other side of the Earth.
Revolution -- Moving Around the Sun
While the Earth spins on its axis, it also moves around the Sun in a fixed path called an orbit. This movement is called revolution. The Earth takes approximately 365 days and 6 hours (about one year) to complete one revolution around the Sun.
How Revolution and Tilt Cause Seasons
Because the Earth's axis is tilted, different parts of the Earth receive different amounts of sunlight during the year. When the northern half (where India is) tilts towards the Sun, we get more sunlight and it is summer. When it tilts away from the Sun, we get less sunlight and it is winter.
Seasons in India
India experiences several seasons during the year:
| Season | Months (approx.) | What Happens |
|---|---|---|
| Summer (Grishma) | March to June | Very hot days; people eat mangoes, drink lassi and nimbu paani |
| Monsoon (Varsha) | July to September | Heavy rains; farmers plant paddy and other kharif crops |
| Autumn (Sharad) | October to November | Pleasant weather; festivals like Dussehra and Diwali |
| Winter (Shishir / Hemant) | December to February | Cold weather; people wear sweaters; festivals like Makar Sankranti, Lohri and Pongal |
| Spring (Vasant) | February to March | Flowers bloom; festival of Holi; pleasant weather |
Leap Year
The Earth takes 365 days and about 6 extra hours to go around the Sun once. Those extra 6 hours add up over four years to make one full extra day (6 hours x 4 = 24 hours = 1 day). So, every four years, we add one extra day to the month of February. Instead of 28 days, February has 29 days in a leap year. A leap year has 366 days instead of 365.
The year 2024 was a leap year. The next leap year will be 2028.
Imagine holding a globe and shining a torch on it in a dark room. Only the side facing the torch is lit up (daytime). The other side is dark (nighttime). Now slowly spin the globe. Different parts move into the light and then into the dark. This is exactly what happens as the Earth rotates -- it creates day and night.
In June, Priya in Chennai feels very hot and uses a fan all day. She drinks tender coconut water to stay cool. At the same time, in December, Vikram in Shimla wears a thick woollen jacket and can see his breath in the cold air. The difference in weather is because of the Earth's tilt -- in June, India tilts towards the Sun (summer), and in December, it tilts away (winter).
Is the year 2032 a leap year? Divide 2032 by 4. If it divides evenly (no remainder), it is a leap year. 2032 divided by 4 = 508 (no remainder). So yes, 2032 is a leap year and February will have 29 days that year.
| Word | Meaning |
|---|---|
| Axis | The imaginary line passing through the North Pole and South Pole around which the Earth spins |
| Rotation | The spinning of the Earth on its own axis (takes about 24 hours) |
| Revolution | The movement of the Earth around the Sun (takes about 365.25 days) |
| Orbit | The fixed path along which the Earth moves around the Sun |
| Geoid | The actual shape of the Earth -- slightly flattened at the poles |
| Leap year | A year with 366 days; February has 29 days (occurs every 4 years) |
What you need: A ball (or an orange), a torch and a dark room.
What to do: Mark a small dot on the ball with a pen -- this dot represents India. Hold the torch steady (this is the Sun). Now slowly spin the ball. Watch how the dot moves into the light (day) and then into the dark (night).
Answer these questions:
Want to use this as a worksheet? Switch to the A4 printable view.
Aarav from Chandigarh called his cousin Nisha in New Zealand one evening. "It is 7 PM here and already dark," said Aarav. "That is strange," replied Nisha, "because here it is morning and the Sun is shining brightly!"
Aarav was puzzled. How can it be night in India and daytime in New Zealand at the same time? The answer lies in how our Earth moves. Let us find out.
Shape of the Earth
Long ago, people thought the Earth was flat. But today we know that the Earth is shaped like a ball -- it is roughly a sphere. Scientists call its exact shape a geoid, which means it is slightly flattened at the top (North Pole) and bottom (South Pole) and slightly bulging at the middle (Equator). Think of it as a ball that has been gently pressed from the top and bottom.
When astronauts from ISRO (Indian Space Research Organisation) and NASA look at the Earth from space, they see a beautiful blue and green sphere.
Think about it: If the Earth is round, why does the ground look flat when we stand on it?
The Earth's Axis
Imagine a thin rod passing through the Earth from the North Pole to the South Pole. This imaginary line is called the axis. The Earth spins around this axis, just like a spinning top. The axis is not straight up and down -- it is tilted at an angle of about 23.5 degrees. This tilt is very important because it causes the seasons.
Rotation -- Spinning on Its Axis
The Earth spins (rotates) on its axis from west to east. It takes approximately 24 hours (one full day and night) to complete one rotation.
How rotation causes day and night: The Sun lights up only one half of the Earth at a time. The half facing the Sun has daytime. The half facing away from the Sun has nighttime. As the Earth keeps spinning, different parts of the Earth move into sunlight and then into darkness. This is why we have day and night.
This is also why when it is night in India, it is daytime in countries like the United States and Brazil, which are on the other side of the Earth.
Think about it: The Earth is spinning right now, but we do not feel it. Why do you think that is?
Revolution -- Moving Around the Sun
While the Earth spins on its axis, it also moves around the Sun in a fixed path called an orbit. This movement is called revolution. The Earth takes approximately 365 days and 6 hours (about one year) to complete one revolution around the Sun.
How Revolution and Tilt Cause Seasons
Because the Earth's axis is tilted, different parts of the Earth receive different amounts of sunlight during the year. When the northern half (where India is) tilts towards the Sun, we get more sunlight and it is summer. When it tilts away from the Sun, we get less sunlight and it is winter.
Seasons in India
India experiences several seasons during the year:
| Season | Months (approx.) | What Happens |
|---|---|---|
| Summer (Grishma) | March to June | Very hot days; people eat mangoes, drink lassi and nimbu paani |
| Monsoon (Varsha) | July to September | Heavy rains; farmers plant paddy and other kharif crops |
| Autumn (Sharad) | October to November | Pleasant weather; festivals like Dussehra and Diwali |
| Winter (Shishir / Hemant) | December to February | Cold weather; people wear sweaters; festivals like Makar Sankranti, Lohri and Pongal |
| Spring (Vasant) | February to March | Flowers bloom; festival of Holi; pleasant weather |
Leap Year
The Earth takes 365 days and about 6 extra hours to go around the Sun once. Those extra 6 hours add up over four years to make one full extra day (6 hours x 4 = 24 hours = 1 day). So, every four years, we add one extra day to the month of February. Instead of 28 days, February has 29 days in a leap year. A leap year has 366 days instead of 365.
The year 2024 was a leap year. The next leap year will be 2028.
Think about it: If you were born on 29th February, how often would your actual birthday come?
| Word | Meaning |
|---|---|
| Axis | The imaginary line passing through the North Pole and South Pole around which the Earth spins |
| Rotation | The spinning of the Earth on its own axis (takes about 24 hours) |
| Revolution | The movement of the Earth around the Sun (takes about 365.25 days) |
| Orbit | The fixed path along which the Earth moves around the Sun |
| Geoid | The actual shape of the Earth -- slightly flattened at the poles |
| Leap year | A year with 366 days; February has 29 days (occurs every 4 years) |
Imagine holding a globe and shining a torch on it in a dark room. Only the side facing the torch is lit up (daytime). The other side is dark (nighttime). Now slowly spin the globe. Different parts move into the light and then into the dark. This is exactly what happens as the Earth rotates -- it creates day and night.
In June, Priya in Chennai feels very hot and uses a fan all day. She drinks tender coconut water to stay cool. At the same time, in December, Vikram in Shimla wears a thick woollen jacket and can see his breath in the cold air. The difference in weather is because of the Earth's tilt -- in June, India tilts towards the Sun (summer), and in December, it tilts away (winter).
Is the year 2032 a leap year? Divide 2032 by 4. If it divides evenly (no remainder), it is a leap year. 2032 divided by 4 = 508 (no remainder). So yes, 2032 is a leap year and February will have 29 days that year.
A. Fill in the Blanks
B. Multiple Choice Questions
C. True or False
D. Short Answer Questions
What you need: A ball (or an orange), a torch and a dark room.
What to do: Mark a small dot on the ball with a pen -- this dot represents India. Hold the torch steady (this is the Sun). Now slowly spin the ball. Watch how the dot moves into the light (day) and then into the dark (night).
Answer these questions: