The Sun, the Moon and the Earth | Class 7 | Geography | Chapter 2 | Maharashtra State Board
In this video, we will explore the relationships between the sun, moon, and earth, and how they move and interact with each other. We will delve into the details of their revolutions and orbits, and explain how they are related to the seasons and the tides. We will also focus on the phases of the moon and their causes, as well as the different types of eclipses that can occur, including solar and lunar eclipses. Throughout the video, we will use visual aids and animations to make the concepts easier to understand and demonstrate the relationships between these celestial bodies. By the end of the video, you will have a better understanding of the motions of the sun, moon, and earth, and how they impact our lives and the natural world.
Questions & Answers
Q.1. Correct the wrong statements. Write down the corrected ones.
1. The moon revolves around the sun.
Ans. Wrong – The moon revolves around the earth.
2. On a full moon day, the moon, the sun and the earth are positioned in this sequence.
Ans. Wrong – On a full moon day, the sun, the earth and the moon are positioned in this sequence.
3. The revolutionary orbits of the earth and the moon are in the same plane.
Ans. Wrong – The revolutionary orbits of the earth and the moon are not in the same plane. The moon’s revolutionary orbit makes an angle of about 5° with that the earth.
4. In one revolution of the moon, its orbit intersects the earth’s orbit only once.
Ans. Wrong – In one revolution of the moon, its orbit intersects the earth’s orbit twice.
5. It is alright to observe a solar eclipse without protecting the eyes.
Ans. Wrong – It is necessary to view the sun disc through dark glasses or through special goggles made for that purpose, otherwise the intense light of the sun can be harmful to the naked eye.
6. An annular solar eclipse occurs when the moon is in the perigee position.
Ans. Wrong – An annular solar eclipse occurs when the moon is in the apogee position.
Q.2. Select the correct option.
1. Solar eclipse.
Ans. (b)
2. The shape of sun disc at the time of annual solar eclipse.
Ans. (b)
3. Apogee position of the moon.
Ans. (c)
Q.3. Complete the following table.
Details | Lunar Eclipse | Solar Eclipse |
Phase of the moon | Full Moon Day | New Moon Day |
Sequence | Moon-Earth-Sun | Earth-Moon-Sun |
Types of Eclipse | Total and Partial | Total, Partial, Annular |
Maximum duration of total eclipse | 107 minutes | 440 Seconds |
Q.4. Draw and label the diagrams.
1. Total and partial solar eclipse.
2. Total and partial lunar eclipse.
Q.5. Answer the following.
1. Why do the sun, the moon and the earth not lie in one and the same line on every full moon and new moon day?
Ans.
The orbital path of the earth and that of moon are not in the same plane.
The moon’s revolutionary orbit makes an angle of about 5° with that of the earth.
On each new moon day, the lines joining the earth and the sun and the moon make an angle of 0° whereas on each full moon day, this angle is 180°.
So, the sun, the earth and the moon may not be in one straight line in the same plane on every new moon or full moon day.
2. When a total solar eclipse occurs why is the partial eclipse also seen from the earth?
Ans.
On a new moon day if the sun, the moon & the earth fall in one line & are in the same plane, the shadow of the moon falls on the earth
This shadow is of two types – the central portion of the shadow is darker & the periphery is light.
In the area where the dark shadow falls, the sun becomes completely invisible. Such an area experiences a total solar eclipse.
However, during the same period, at the places where the shadow is lighter, the sun disc appears partially covered. Such an area experience partial solar eclipse. Thus when a total solar eclipse occurs a partial eclipse is also seen from the earth.
3. Suggest measures that can be taken to eradicate the superstitions related to the eclipses.
Ans. The following measures can be taken to eradicate superstition related to eclipses:
Use of media to create awareness.
Parental guidance to help think logically.
Teachers guidance to help students develop a scientific outlook.
Campaigns, public meetings and lectures especially in rural areas to eradicate superstitions.
4. What precautions should we take while observing a solar eclipse?
Ans. The precautions to be taken while observing a solar eclipse are:
We should not observe a solar eclipse with naked eyes as the intense light of the sun can harm them.
We must use dark glasses or goggles that are specially designed for viewing the solar eclipse.
5. What types of Solar eclipses will occur in perigee conditions?
Ans. Total and Partial solar eclipse will occur in perigee condition.
(1) Total solar eclipse :
On a new moon day, the sun, the moon the earth are in a straight line & the shadow of the moon falls on the earth.
The area of dark shadow falls on the earth, the sun becomes completely invisible. This condition is known as total solar eclipse.
(2) Partial solar eclipse:
However during the same period at places where the shadow is lighter, the sun disc appears partially covered, this condition is described as partial solar eclipse.
E X T R A
Q.1. Fill in the blanks choosing the correct option from the brackets.
The shape of the moon’s orbit is elliptical. (round, elliptical, square)
The moon has axial and orbital motions. (axial, orbital, elliptical)
When the moon is closest to the earth it is said to be in perigee. (apogee, perigee, orbit)
When the moon is farthest to the earth it is said to be in apogee. (apogee, perigee, arial)
Solar Eclipse occurs on the new moon day. (full moon, new moon, quarter moon)
Lunar Eclipse occurs on the full moon day. (full moon, new moon, quarter)
Annular solar eclipse is a rare phenomenon. (Total, Partial, Annular)
When the shadow of the moon on the central portion of the earth is darker while the periphery is lighter it is known as a total solar eclipse. (partial, total, lunar)
When the shadow of the moon on the central portion of the earth is lighter and the sun disc appears to be partially covered, it is known partial solar eclipse. (total, partial, solar)
The moon is semi circular when the earth, the moon and the sun make an angle of 90°. (full, semi circular, crescent)
Occultation occurs with reference to the moon. (sun, moon, earth)
Transit is associated with the sun. (sun, moon, earth)
During the period of solar eclipse, a large number of birds and animals get confused. (solar, lunar, annular)
Q.2. Correct the wrong statements. Write down the correct ones.
1. When the moon is closest to the earth it is said to be in apogee and when it is the farthest, the position is called perigee.
Ans. Wrong – When the moon is closest to the earth it is said to be in perigee and when it is the farthest, the position is called apogee.
2. The moon wanes from the new moon day to the full moon day and waxes from the full moon to the new moon day.
Ans. Wrong – The moon waxes from the new moon day to the full moon day and wanes from the full moon to the new moon day.
Q.3. Name the following.
1. Motions of the moon.
Ans. Axial and orbital motion.
2. Types of solar eclipse.
Ans. Total solar eclipse, Partial solar eclipse, Annular solar eclipse.
3. Types of lunar eclipse.
Ans. Total lunar eclipse and Partial lunar eclipse.
4. Eclipse that confuses animals and birds.
Ans. Solar eclipse.
5. An example of occultation.
Ans. Total solar eclipse.
6. The event of the occurrence of solar eclipse or lunar eclipse.
Ans. Astronomical event.
Q.4. Define the following.
1. Perigee.
Ans. When the moon is the closest to the earth in its orbit, it is perigee.
2. Apogee.
Ans. When the moon is at the farthest from the earth in its orbit, it is apogee.
3. Occultation.
Ans. The moon revolves around the earth. While doing so, it obscures a star or a planet and that celestial body appears to hide behind the moon. This is called occultation.
4. Transit.
Ans. If an inner planet like Mercury or Venus comes in between the line of the earth and the sun, a transit occurs. At that time a small dot appears to move across the sun’s disc.
5. Phases of the moon.
Ans. The illuminated portion of the moon disc observed from the earth that keeps on changing every day within a lunar month are called the phases of the moon.
6. Solar Eclipse.
Ans. If the moon comes between the earth and the sun in a straight line on new moon day, the shadow of the moon falls on the earth and the sun becomes totally or partially invisible in the shadow zone. This phenomenon is called the solar eclipse.
7. Lunar Eclipse.
Ans. On a full moon day, the . moon’s path of revolution passes through the thick shadow of the earth and the moon becomes totally or partially invisible. This phenomenon is called lunar eclipse.
8. Annular Solar eclipse.
Ans. Sometimes when the moon is in apogee position, a deep shadow of the moon is cast in space & does not reach the earth. From a very small region of the earth, only an illuminated edge of the sun disc is seen in the form of a ring. This is called annular solar eclipse.
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