The Earth experiences day and night because it rotates on its axis. The axis is an imaginary line that runs through the center of the Earth from pole to pole. The Earth rotates counterclockwise, completing one rotation every 24 hours.

As the Earth rotates, different parts of the Earth are exposed to the sun’s rays. The part of the Earth that is facing the sun is in daylight, while the part of the Earth that is not facing the sun is in darkness.

The length of day and night varies depending on the time of year and the location on Earth. Near the equator, the days and nights are almost equal throughout the year. However, at the poles, the days and nights can be very long or very short.

In the summer, the days are longer and the nights are shorter at the poles. In the winter, the days are shorter and the nights are longer. This is because the Earth’s axis is tilted by 23.5 degrees. As the Earth orbits the sun, the Northern Hemisphere is tilted towards the sun in the summer and away from the sun in the winter. This is why the Northern Hemisphere has longer days and shorter nights in the summer and shorter days and longer nights in the winter.

The tilt of the Earth’s axis also causes the seasons to change. The seasons are caused by the amount of sunlight that different parts of the Earth receive. In the summer, the Northern Hemisphere receives more sunlight than in the winter. This is why the Northern Hemisphere has warmer summers and colder winters.

The rotation of the Earth and the tilt of its axis are the two main reasons why we experience day and night and the seasons.