The Sky in your Hands
When we look up into the sky on a clear night, the Earth's rotation around its axis makes it appear as though the stars are rotating slowly around us in an east to west direction. If you set the sphere's axis to the 39º mark, which is the approximate latitude of Valencia, you will be able to observe the apparent movement of the celestial sphere by simply rotating the sphere from east to west. Curiously there are some constellations which never disappear below the horizon and are visible throughout the entire night. These are known as circumpolar stars because they appear to rotate around the celestial pole. In the northern hemisphere, the celestial pole corresponds to the Northern Star. If you change the latitude of the sphere, you will see that the night sky also changes with respect to the place of observation.
On the equator, the paths taken by the Sun, Moon and stars as they rise and set are approximately perpendicular to the horizon. You can observe this phenomenon by setting the rotational axis to 0º, which is the latitude at the equator, and then rotating the sphere.