Answer:
The observed shortening of daylight hours over the month could be due to the changing seasons. If the month in question is during the fall or autumn season, this could explain the reduction in daylight hours. During this time, the Northern Hemisphere is tilting away from the Sun, resulting in shorter days and longer nights. As the tilt continues, the amount of daylight hours continues to decrease until the winter solstice, which is the shortest day of the year. Therefore, the student's observations are likely a result of the seasonal change and the angle of Earth's tilt in relation to the Sun.