Formation of Day and Night: The alternation between day and night is a result of Earth's rotation on its axis. This rotation causes different parts of the Earth to be exposed to the Sun's light, creating the cycle of day and night.

1. Earth's Rotation:
   • Earth rotates on its axis, an imaginary line that runs from the North Pole to the South Pole.
   • It takes approximately 24 hours for Earth to complete one full rotation.
2. Daytime:
   • When a specific part of Earth is facing the Sun, it is illuminated by sunlight. This part experiences daytime.
   • The side of the Earth facing the Sun receives direct sunlight, making it brighter and warmer.
3. Nighttime:
   • As Earth continues to rotate, the illuminated side faces away from the Sun, resulting in nighttime.
   • During the night, the area is no longer directly exposed to sunlight, leading to darkness and cooler temperatures.
4. Sunrise and Sunset:
   • Sunrise occurs when the edge of the Earth facing the Sun begins to receive direct sunlight, marking the start of a new day.
   • Sunset occurs when the illuminated side of Earth rotates away from the direct sunlight, leading to the end of the day.
5. Terminator Line:
   • The boundary between the illuminated hemisphere (day) and the dark hemisphere (night) is called the terminator line.
6. Day and Night Around the World:
   • Due to Earth's rotation, different parts of the world experience day and night at various times.
   • As Earth rotates, the Sun appears to move across the sky, causing daylight to shift from east to west.

The formation of day and night is a fundamental aspect of our daily lives, influencing our activities, sleep patterns, and the functioning of ecosystems. Earth's rotation on its axis is what creates the cycle of light and darkness that we observe as day and night.