Std 5 EVS 1 · Chapter 2

2. Motions of the Earth

Complete solutions to the Exercise. Maharashtra State Board (Balbharati), Standard 5 EVS 1.

Exercise

1What’s the solution? Amit wants to take his granny to Australia, which is in the southern hemisphere. But she cannot bear very cold weather. When should they make this trip?

They should travel when it is summer in Australia — that is, during the months of December to February, which are our winter months in India.

Australia lies in the southern hemisphere. When the southern hemisphere is tilted towards the sun, it receives slanting rays for a shorter time and gets summer, while the northern hemisphere has winter at the same time. So the seasons in Australia are the opposite of ours. If Amit and his granny travel during the Indian winter, they will reach Australia in its warm season and his granny will not have to face the cold.

Remember: if they went during the Indian summer (May–June), it would be winter in Australia — exactly what his granny cannot bear.

2Use your brain power!

(a) How many rotations does the earth complete during one revolution around the sun?

The earth completes one rotation on its axis in one day, and it takes about 365 days to complete one revolution around the sun. So the earth rotates roughly 365 times during a single revolution.

(b) It is sunrise at Itanagar in Arunachal Pradesh. Write the names of the following cities in the order in which the sun will rise there — Mumbai (Maharashtra), Kolkata (West Bengal), Bhopal (Madhya Pradesh), Nagpur (Maharashtra).

The earth rotates from west to east, so the sun rises first in the places that lie furthest to the east. Itanagar is in the far east of India, so after Itanagar the sun will rise in this order:

1. Kolkata — West Bengal, the easternmost of the four

2. Nagpur — eastern Maharashtra

3. Bhopal — Madhya Pradesh, a little further west

4. Mumbai — on the west coast, so the sun rises there last

How to work it out: arrange the cities from east to west on the map of India. The city furthest east sees the sunrise first.

3Fill in the blanks.

(a) The motion of the earth around itself is called rotation.

(b) The motion of the earth around the sun is called revolution.

4What is meant by each of the following terms?

(a) Full moonThe night on which the whole of the moon’s face that we see from the earth is lit by the sun. The moon appears as a complete bright circle in the sky.

(b) New moonThe night on which the side of the moon facing the earth gets no sunlight at all, so the moon cannot be seen in the sky.

(c) Lunar monthThe period from one new moon to the next, which is of about 28 to 30 days.

(d) TithiEach single day of the lunar month is called a tithi.

5Answer the following questions.

(a) What is the equator?

If a circle is drawn all around the surface of the earth exactly midway between the north pole and the south pole, it divides the earth into two equal parts. This imaginary circle is called the equator.

(b) What are the two parts of the earth made by the equator?

The equator divides the earth into two equal halves. The half lying to the north of the equator is called the northern hemisphere and the half lying to the south of it is called the southern hemisphere. India lies in the northern hemisphere and Australia in the southern hemisphere.

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