What causes difference in length of days and nights

The primary cause for the difference in the length of days and nights is the tilt of the Earth's axis relative to its orbital plane around the Sun. This tilt is approximately 23.5 degrees. Step 1: As the Earth orbits the Sun, its axial tilt remains pointed in the same direction in space. This means that at different points in the orbit, different hemispheres are tilted more directly towards or away from the Sun. Step 2: When a hemisphere is tilted towards the Sun, it receives more direct sunlight and for a longer duration during its rotation. This results in longer daylight hours and shorter nights, characteristic of summer. Step 3: Conversely, when a hemisphere is tilted away from the Sun, it receives less direct sunlight and for a shorter duration. This leads to shorter daylight hours and longer nights, characteristic of winter. Step 4: The points where the tilt is neither towards nor away from the Sun are the equinoxes, resulting in approximately equal day and night lengths globally.