how earth rotates?
http://www.windows.ucar.edu/tour/link=/the_universe/uts/earth2.html
It just does. There is very little friction to slow it down, but there is some slowing down due to tides and the moon - about one second every ten years. The rotation has been going on since Earth was formed, as the original angular momentum was conserved.
The sources I've come across indicate a much slower rate of slowing than the one given above. One gives a value of 0.005 seconds per year, another says 2 milliseconds since 1820, yet another gives an increase in the length of the day of 0.0017 seconds (or 1.7 milliseconds) for the century. See "Tidal Acceleration" in Wikipedia for a description of the process itself, with links to other sources.
The Earth rotates on its axis, which is an imaginary line running through its center, from the North Pole to the South Pole. This rotation causes day and night. The Earth completes one full rotation in about 24 hours, resulting in a 24-hour day.
To understand how the Earth rotates, you can try a simple experiment. Take a ball, such as a basketball or a globe, and hold it vertically. Place your finger on the top of the ball, representing the North Pole, and another finger on the bottom, representing the South Pole. Now rotate the ball slowly and smoothly from west to east. This represents the Earth's rotation.
In reality, the Earth rotates due to its initial angular momentum acquired during its formation billions of years ago. The exact mechanism of this initial rotation is believed to be influenced by factors such as the collision of celestial objects and gravitational forces.
It's important to note that the Earth's rotation is responsible for phenomena such as the rising and setting of the Sun, the movement of stars across the sky, and the Coriolis effect, which influences the direction of winds and ocean currents.