Motions of the Earth-1

Motions of the Earth

Part-1

Lesson-3

Wonder facts

Nicolaus Copernicus, a Polish astronomer, in the sixteenth century was the first to say that earth not only spins on its axis but also moves around the sun

Two types of motions of the earth

• Rotation- movement of the earth on its axis

• Revolution- movement of the earth around the sun

Rotation

1. The earth rotates on its axis from west to east.

2. The axis is an imaginary line which passes through its centre

3. Axis is inclined at an angle of 66½° with the plane of the earths orbit

4. Inclination is always towards pole star

5. Due to the spherical shape of the earth, only half of it gets light from the sun at a time

6. The portion facing the sun experiences day while the other half away from the sun experiences night.

7. The circle that divides the day from night on the globe is called the circle of illumination

8. The earth takes about 24 hours to complete one rotation around its axis.

9. The period of rotation is known as the earth-day.

10. Days and nights are caused due to rotation

11. It causes the bulging of the earth at the equator flattening at the poles

What would happen if the earth did not rotate?

Answer

• Life would not be possible

• Half part will remain facing the sun, will become hot

• Half part will remain in darkness, will freeze

Quiz Time

Speed of rotation of the earth

• Circumference of the earth at equator = 40,000 Km

• Time taken by earth to complete rotation = 24 hours

• Speed of the rotation = ?

• (Hint: Speed = Distance/ Time)

Multiple Select

So speed of rotation is

• 1,275 km per hour

• 1,475 km per hour

• 1,675 km per hour

• 1,875 km per hour

Multiple Choice

The circle that divides the day from night on the globe is called _____________

• circumference

• circle of distraction

• rotation

• circle of illumination

Multiple Choice

Movement of the earth around the sun is called

• Rotation

• Revolution

Multiple Choice

Period of rotation of the earth is called

• earth hour

• earth day

• earth-movement

• earth-circle