Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?
Answer:
Pour one of the glasses of milk into an empty glass.
I appear in the morning. But am always there. You can never see me. Though I am everywhere. By night I am gone, though I sometimes never was. Nothing can defeat me. But I am easily gone.