Final answer:
People throughout history noticed longer nights in winter by observing the changing patterns of sunrise and sunset, which were used to develop the first calendars. The tilt of the Earth's axis causes variations in daylight, leading to shorter days and longer nights during the winter months in each hemisphere.
Step-by-step explanation:
Throughout history, people noticed that nights were longer in the winter partly due to the observations made by ancient cultures. Cultures like the Babylonians who tracked sunrise and sunset times found regular changes with these events, and this was instrumental in the creation of the first calendars.
The lengthening and shortening of days were hard not to notice, especially since these changes affected agriculture and daily life. As the Earth is tilted on its axis, during winter in a hemisphere, that part of Earth is tilted away from the Sun, leading to shorter days and longer nights.
In more modern times, the difference in daylight hours can be explained by astronomy, as we understand that the Earth's tilt causes variations in daylight throughout the year, resulting in the observed changes in day length. Today, scientific tools and observations confirm this seasonal shift of daylight which ancients noticed by simply observing the horizon and recognizing the seasonal patterns over time.