# Class 5 SST Chapter 3 Important Notes

Class 5 SST Chapter 3 Important Notes from Movements of the Earth – Rotation, and Revolution

The Earth is very big and we are also moving with the Earth. So we don’t feel the movements of the Earth.

The Earth moves in two different ways.

1. Rotation – About its own axis
2. Revolution – In a fixed path around the Sun

## Rotation of the Earth

The Earth rotates or spins about its axis. The Earth rotates from the west to east direction. So one by one all the places come in front of the Sun. This cycle goes on everyday.

The places which receive the sunlight will experience day and the dark places will experience night.

Thus the rotation of the Earth causes the day and night. The Earth takes 24 hours to complete one rotation. Hence we have one full day (one day + one night) of 24 hours.

 Image by Arek Socha from Pixabay

### Revolution of the Earth

(Class 5 SST Chapter 3 Important Notes)

Revolution means making rounds around something.

The Earth moves in a fixed path around the Sun. This fixed path is called an orbit. The Earth takes 365 days and 6 hours to complete one revolution around the Sun. Therefore, we have one year of 365 days. We avoid these 6 hours for our convenience.

Each we get 6 hours every year and after 4 years, it becomes 24h hours i.e. 1 day.

So 1 day is added to every 4th year. This year with 366 days is called a leap year.

### Formation of Seasons

(Class 5 SST Chapter 3 Important Notes)

Since the Earth is tilted at an angle of 23.5 degrees. While moving around the Sun, different parts of the Earth receive different amounts of heat due to the tilt of the Earth.

The part which is near and towards the Sun will receive more heat and it will have a summer season.

The part which is a little far and away from the Sun will receive less amount of heat and it will have winter season.

This is the reason we have different seasons in different parts of the World.

 Different positions of the Earth over a year andImportant days with respect to these positions of the Earth.

### Main Seasons on the Earth

• Summer
• Winter
• Autumn
• Spring

#### Summer and Winter Season

(Class 5 SST Chapter 3 Important Notes)

In the month of June, the North Pole is tilted towards the Sun, and the South Pole is tilted away from the Sun. So the Northern Hemisphere will receive more heat and the Southern Hemisphere will receive less heat.

Therefore, the Northern Hemisphere will have summer in the month of June and the Southern Hemisphere will have winter in the month of June.

In the month of December, the Southern Hemisphere will have summer and the Northern Hemisphere will have winter.

#### Autumn and Spring Seasons

(Class 5 SST Chapter 3 Important Notes)

In the month of March and September, both the Poles are at an equal distance. Hence both the hemispheres receive an equal amount of heat.

In March, the Northern Hemisphere will have spring and the Southern Hemisphere will have autumn.
In September, the Northern Hemisphere will have autumn and the Southern Hemisphere will have spring.

Thus due to the tilt of the Earth, the Northern and the Southern Hemispheres experience the opposite seasons.