1.3 The Earth

WHAT are we going to learn?

• The shape, appearance and composition of the Earth.
• The Earth's movements.
• Why we have day and night and four seasons.

The Earth song 

Day and night cycle

Day and night vary in length according to the season and your distance from the Equator. At the Equator, day and night are approximately the same length all year round. At the Poles the effect is extreme. In Summer you experience the midnight sun while in Winter the polar night lasts 24 hours.

Why do we have seasons?

It takes the Earth just 365 days to orbit the Sun. During this period we experience different seasons because the Earth's axis is tilted. As a result, our part of the planet receives more or less light during different months.

Solstices and equinoxes

The day that the Earth's North Pole is tilted closest to the sun is called the summer solstice. This is the longest day of the year for people living in the northern hemisphere. 

The winter solstice, or the shortest day of the year, happens when the Earth's North Pole is tilted farthest from the Sun.

In between, there are two times when the tilt of the Earth is zero, meaning that the tilt is neither away from the Sun nor toward the Sun. These are the vernal equinox — the first day of spring — and the autumnal equinox – the first day of fall. Equinox means "equal." During these times, the hours of daylight and night are equal. Both are 12 hours long.