Our Earth is always moving in two important ways: rotation and revolution. Rotation is the Earth’s spin on its axis. One complete rotation takes about 24 hours and causes day and night. The side facing the Sun has day; the opposite side has night. Because the axis is tilted by 23½°, the Sun’s rays fall differently on different parts of the Earth during the year.

Revolution is the Earth’s journey around the Sun along a fixed orbit. One revolution takes 365¼ days. To adjust the extra quarter day, every fourth year is a leap year with 366 days. Revolution, together with the tilt of the axis, causes the seasons. When the Northern Hemisphere is tilted towards the Sun, it receives more direct sunlight and has summer; the Southern Hemisphere has winter. Six months later, the situation reverses.

Two special days are called solstices. Around 21 June (Summer Solstice), the Northern Hemisphere has the longest day; the Sun is overhead at the Tropic of Cancer. Around 22 December (Winter Solstice), it has the longest night; the Sun is overhead at the Tropic of Capricorn. Two other important days are the equinoxes, when day and night are equal everywhere: 21 March (Vernal/Spring) and 23 September (Autumnal).

These movements also explain time differences across the world and why places like Japan are called the “Land of the Rising Sun”. Understanding rotation and revolution helps us read calendars, plan seasons, and know why temperatures and daylight vary through the year.

पृथ्वी दो महत्त्वपूर्ण प्रकार से निरन्तर गतिशील रहती है—घूर्णन (Rotation) और परिक्रमण (Revolution)। घूर्णन का अर्थ है पृथ्वी का अपनी धुरी (Axis) पर घूमना। इसकी एक परिक्रमा लगभग 24 घंटे में पूरी होती है, जिससे दिन-रात होते हैं। जिस भाग पर सूर्य की किरणें पड़ती हैं वहाँ दिन, और दूसरी ओर रात होती है। पृथ्वी की धुरी 23½° झुकी है, इसलिए सूर्य की किरणें साल भर अलग-अलग भागों पर अलग मात्रा में पड़ती हैं।

परिक्रमण का अर्थ है पृथ्वी का सूर्य के चारों ओर तय कक्षा (Orbit) में घूमना। एक परिक्रमण 365¼ दिन में पूरा होता है। अतिरिक्त ¼ दिन को जोड़ने के लिए प्रत्येक चौथा वर्ष लीप ईयर कहा जाता है, जिसमें 366 दिन होते हैं। परिक्रमण और धुरी का झुकाव मिलकर ऋतुओं का निर्माण करते हैं—जब उत्तरी गोलार्ध सूर्य की ओर झुका होता है तो वहाँ गर्मी और दक्षिणी गोलार्ध में सर्दी होती है; छह महीने बाद स्थिति उलट जाती है।

दो विशेष दिनों को अयनांत (Solstice) कहते हैं—लगभग 21 जून को ग्रीष्म अयनांत (सबसे लम्बा दिन, सूर्य कर्क रेखा पर सीधा), और लगभग 22 दिसम्बर को शीत अयनांत (सबसे लम्बी रात, सूर्य मकर रेखा पर सीधा)। इसके अलावा विषुव (Equinox) होते हैं—21 मार्च (वसंत) और 23 सितम्बर (शरद)—जब पूरे पृथ्वी पर दिन और रात बराबर होते हैं।

इन्हीं गतियों से दुनिया भर में समय का अंतर समझ आता है और जापान को “उगते सूर्य की भूमि” क्यों कहा जाता है, यह भी स्पष्ट होता है। इसलिए घूर्णन और परिक्रमण का ज्ञान कैलेंडर, मौसम और दैनिक जीवन के लिए बहुत उपयोगी है।

A) Choose the correct words and fill up the blanks ✅

1. The fixed path which the earth takes to revolve around the sun is known as orbit.
2. The earth takes 365¼ days to revolve around the sun.
3. A leap year has 366 days.
4. The word equinox means equal day and night.
5. On 21 March, we have spring equinox.

B) Match the columns 🔗

C) State whether True or False. Rewrite the false statements correctly ✍️

1. The two movements of the earth are rotation and revolution. — True
2. The country that is known as the ‘Land of the Rising Sun’ is India. — False. Correction: It is Japan.
3. Rotation causes seasons. — False. Correction: Revolution (along with the earth’s tilt) causes seasons.
4. The main effect of revolution is that it causes day and night. — False. Correction: Rotation causes day and night.
5. Seasons are caused due to the revolution of the earth around the sun and also due to the tilt of the earth’s axis. — True

D) Unscramble the letters to form the correct words 🔤

1. XIAS → AXIS
2. OTTRIOAN → ROTATION
3. OINTERVOUL → REVOLUTION
4. LPAE AREY → LEAP YEAR
5. ESSANO → SEASONS

E) Answer the following questions 🗣️

1. Which are the two important movements of the earth? Explain.
   The two movements are rotation and revolution. Rotation is the spinning of Earth on its axis in about 24 hours, causing day and night. Revolution is Earth’s movement around the Sun in an orbit taking 365¼ days; with the axis tilt, it causes seasons.
2. How are seasons caused?
   Seasons occur due to the revolution of the Earth around the Sun and the 23½° tilt of its axis. The hemisphere tilted towards the Sun receives more direct rays and has summer, while the other has winter; during equinoxes day and night are equal.
3. What are the four main seasons?
   Spring, Summer, Autumn (Fall) and Winter (in the Northern Hemisphere).
4. What are the spring and autumnal equinoxes?
   Around 21 March (spring/vernal) and 23 September (autumnal) the Sun is overhead at the Equator and day and night are equal all over the world.
5. Explain the position of the earth during summer solstice (with a diagram).
   On about 21 June, the Northern Hemisphere is tilted towards the Sun; the Sun’s vertical rays fall on the Tropic of Cancer (23½° N). Northern regions have the longest day and shortest night (summer), while the Southern Hemisphere has winter.