Class 7 Science - WEST-BENGAL
Earth, Moon and the Sun
The chapter 'Earth, Moon and the Sun' for Class 7 West Bengal Board (WBBSE) students explores the fascinating cosmic relationship between our planet and its two primary celestial neighbours. Students learn about the movements of the Earth and Moon, including rotation and revolution, which cause day and night and changes in seasons. The chapter also details the fascinating phenomena of solar and lunar eclipses, phases of the Moon, and gravitational forces. Understanding these concepts is vital for WBBSE board exams as it forms the foundational astronomy knowledge tested frequently through diagrams, short-answer questions, and conceptual queries.
Start Learning FreeKey Concepts
Rotation of the Earth
The spinning of the Earth on its imaginary axis from west to east, which takes 24 hours and causes day and night.
Revolution of the Earth
The movement of the Earth around the Sun in a fixed elliptical orbit, taking 365 days and 6 hours to complete, which causes changes in seasons.
Phases of the Moon
The changing shapes of the bright part of the Moon as seen from Earth, caused by its revolution around the Earth and changing positions relative to the Sun.
Solar Eclipse
A phenomenon that occurs when the Moon comes directly between the Sun and the Earth, blocking the Sun's light and casting a shadow on Earth.
Lunar Eclipse
A phenomenon that occurs when the Earth comes directly between the Sun and the Moon, casting its shadow on the Moon during a full moon night.
Important Formulas
Board Exam Info
In the West Bengal Board (WBBSE) Class 7 science examination, this chapter typically carries around 6 to 10 marks. Common question types include short objective questions, fill-in-the-blanks, distinguishing between solar and lunar eclipses, and drawing or labeling diagrams of eclipses and moon phases.
Frequently Asked Questions
Why do we see only one side of the Moon from the Earth?
The Moon's rotational period on its own axis is almost the same as its revolution period around the Earth (synchronous rotation), which is about 27.3 days. Hence, the same side always faces the Earth.
What is the main difference between a solar eclipse and a lunar eclipse?
In a solar eclipse, the Moon comes between the Sun and the Earth. In a lunar eclipse, the Earth comes between the Sun and the Moon.
Why is it warmer in summer and colder in winter?
It is due to the tilt of the Earth's axis. When the Northern Hemisphere tilts towards the Sun, it receives direct sunlight, causing summer, and vice versa.
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