The Earth: origin, rotation and revolution
- Origin of earth
- Evolution of the atmosphere and oceans by degassing
- Rotation and revolution
- Axial tilt of 23.5 degrees, solstices, equinoxes and the seasons
- Variation of day length with latitude and season; midnight sun at the polar circles
- Finding direction from the Pole Star and the Sun
- Geological time scale: eons, eras and periods