The Moon moves round the Earth and Earth moves round the Sun. Our whole Solar System moves bringing changes like day and night and change in seasons.

The Earth spins around in axis and complete one rotation in 24 hours. As it spins, some places face the sun and get light. These places have day. The places not facing the sun have night. As the earth is spinning continuously, the change from day to night and back again goes on. The Earth spins towards the east. So, the Sun seems to rise in the east, and set in the west. Sun doesn’t move across the sky, Earth moves. The sun seems to move because we look at it from the perspective of Earth. Shadow lengths change during the day; the shortest length is during mid-day.

The earth orbits around the Sun. It takes 365 days and nights to make a complete orbit around the Sun. While orbiting round the Sun, the earth tilts slightly to one side by 23.5 degree. The north end of the axis always point towards North Star as the earth circles th Sun. The tilted axis and yearly orbiting causes the variation in the amount of heat at different locations on the Earth causing seasonal changes.

Twice in the year the sun is furthest from the equator. This refers to "Solstice".

1. The summer solstice is when the sun is furthest north from the equator. This happens about June 21. So, there is summer in Northern Hemisphere and most hours of daylight. Southern Hemisphere have winters.
2. The winter solstice is when the sun is furthest south from the equator. This happens about December 22. So, there is summer in Southern Hemisphere and winter in Northern Hemisphere.

Key Facts

• The Earth spins around once every 24 hours.
• The Earth takes one year to orbit the Sun.
• The Moon takes one month to orbit the Earth.
• The Sun lights up half the Earth.
• The seasons occurs because the Earth is tilted.