SOCIAL SCIENE: Planet Earth

PLANET EARTH

1. Earth Movements

We can distinguish 2 movements in planet Earth:

- Rotation: The Earth moves around its axis. It takes 24 hours (1 day) and it causes day and night.

- Revolution: The Earth moves around the Sun. It takes exactly 365 days + 6 hours. If we collect these hours in 4 years we have 24 hours. For this reason we have a Leap year (366 days) every four years. This movement causes the 4 seasons: spring, summer, autumn and winter.

2. Imaginary lines: parallels and meridians

PARALLELS: They are horizontal lines from East to West and they are lines of latitude.

     The most important parallels are:

-Equator

- Tropics of Cancer and Capricorn

- Artic and Antartic Circles.

   MERIDIANS: They are vertical lines from North to south and      they are lines of longitude.

The most importan meridian is Prime Meridian or Meridian of Greenwich.