Orbital dawn

http://www.esrl.noaa.gov/gmd/obop/spo/livecamera.html

As the Earth moves through space and around the Sun it turns as a component of its orbital motion. The South pole is 23 1/2 degrees above the fully illuminated face of the Earth and although the Sun has yet to appear, like its counterpart daily surface rotation, dawn comes before the appearance of the Sun.

As students return to classrooms, it would be great if teachers just explained the Earth's tow daylight/darkness cycles going on simultaneously and the different types of surface rotations as the cause of those cycles.