Rotation
Rotation refers to the movement of the Earth on its axis. The Earth rotates or spins on an imaginary line called its axis, which runs through its center from the North Pole to the South Pole. This rotational movement takes approximately 24 hours to complete one full rotation, resulting in the cycle of day and night.

Key Points:
- Rotation is responsible for the Earth's daily cycle of day and night.
- The axis of the Earth remains tilted at an angle of about 23.5 degrees.
- As the Earth rotates, different parts of the planet are exposed to sunlight, creating the cycle of day and night.
- The rotation of the Earth also affects the direction of winds, ocean currents, and the movement of celestial bodies in the sky.

Day and Night:
- When a particular region of the Earth is facing towards the Sun, it experiences daylight, resulting in daytime.
- As the Earth continues to rotate, that region moves away from the Sun, causing darkness and resulting in nighttime.
- The cycle of day and night occurs because of the Earth's rotation on its axis.

Effects of Rotation:
- The rotation of the Earth affects the direction of winds. The movement of air from high-pressure areas to low-pressure areas is caused by the rotation of the Earth.
- It also affects the movement of ocean currents. The rotation of the Earth influences the direction and speed of ocean currents.
- The rotation of the Earth affects the apparent movement of celestial bodies in the sky. Stars, planets, and other celestial objects appear to move across the sky due to the Earth's rotation.

Conclusion:
In conclusion, the movement of the Earth on its axis is called rotation. This rotational movement is responsible for the cycle of day and night, affects the direction of winds and ocean currents, and influences the apparent movement of celestial bodies in the sky.