Keeping Time with the Skies | Class 8 Science Notes

Day and Night

This section explains the phenomenon of day and night as a result of Earth's rotation. Earth spins around its axis once approximately every 24 hours. This rotation causes different parts of the Earth to face the Sun at different times, resulting in day when a region faces the Sun and night when it faces away. The axis of Earth is an imaginary line passing through the North and South Poles. The rotation is from west to east, which makes the Sun appear to rise in the east and set in the west. The concept of the globe is introduced to demonstrate this rotation and the resulting day and night cycle. The section also discusses the apparent movement of the Sun across the sky and how shadows change during the day. It highlights that the length of day and night can vary depending on the Earth's tilt and position in its orbit, which is further elaborated in later sections.

📊 Diagram: Diagram of Earth showing rotation on its axis with day side illuminated by the Sun and night side in darkness. Also shows the direction of rotation and the position of the Sun.

🧪 Activity: Activity: Using a globe and a torch to demonstrate day and night by rotating the globe and observing illuminated and dark parts.

🔗 Connection: Prepares for the next section on the Moon and its phases, connecting the concept of celestial motion to time measurement.