Lesson 1 of 4 · Grade 7 Social Studies
The earth and the solar system
15 min
The solar system is made of the sun and everything that moves around it: eight planets, moons, asteroids and comets.
The eight planets (from the sun)
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
- Jupiter is the largest planet. Mercury is the closest to the sun.
Movements of the earth
- Rotation: the earth spins on its axis once every 24 hours. This causes day and night.
- Revolution: the earth moves around the sun once every 365¼ days. This causes seasons. Every fourth year (leap year) has 366 days.
Shape of the earth
The earth is a sphere slightly flattened at the poles. Evidence: ships disappear gradually over the horizon, photographs from space, and the round shadow of the earth on the moon during a lunar eclipse.
Key points to remember
- Eight planets orbit the sun
- Rotation causes day and night (24 hours)
- Revolution takes 365¼ days and causes seasons
- Jupiter is the largest planet
Test yourself
