Seasons

The Earth is spinning around an imaginary line called its axis. The axis passes through the north pole and south pole. The reason for day and night is that the Earth is rotatingaround its axis. As the Earth spins about its axis it revolvesaround the Sun on its orbit path. So, to summarize each time the Earth rotates around its axis 1 dayhas been completed and every time the Earth completes one revolution 1 yearhas been completed. One day is 24 hours long and one year is 365.25days long. The Earth is tiltedon its axis so that the north and south pole are not straight up and down, but slanted at an angel of 23.5degrees. Because of this tilt the amount of direct sunlight received at different points on the Earth changes throughout the year. This is why we have seasons. As the Earth revolves around the sun the angle of solar radiation changes for different parts of the world. When the northern hemisphere experiences summer the southern hemisphere experiences winter. Matching Summer The time of year when sunlight is most direct. Rotation Spin Revolution Orbit Hemisphere Half of the Earth Equator The middle line of latitude. 23.5 degrees Tilt of the Earth on its axis.