It is not possible for an individual observer to see both day and night simultaneously in the same location. The occurrence of day and night is a result of the rotation of the Earth on its axis, combined with its position relative to the Sun.
As the Earth rotates, different parts of the planet are exposed to sunlight, experiencing daytime, while other parts are facing away from the Sun, resulting in nighttime. This cycle gives rise to the daily alternation between day and night.
However, there are certain scenarios where different locations on Earth can experience different times of day simultaneously. This is primarily due to the Earth's spherical shape and its division into time zones. Each time zone represents a specific region with a designated standard time based on the average solar time for that longitude.
For example, when it is daytime in one part of the world, it can be nighttime in another part that is located in a different time zone. People in these two locations would experience different times of day. Additionally, there are also phenomena like the Midnight Sun and Polar Night that occur in the polar regions during certain times of the year, where the Sun remains visible for 24 hours or is completely absent for an extended period.
In summary, while different parts of the Earth can experience different times of day simultaneously due to time zone divisions, it is not possible for an individual observer to witness both day and night in the same location at the same time.