Walk in a circle around your partner while you keep facing the same direction. (Use a distant object to be sure you keep facing the same direction and aren't rotating.) Have your partner note whether all or only one side of you can be seen during your "orbit." Discuss the results in the context of the rotation of the Moon (Figure 9.2).
Working with a partner, get a plastic dish of flour and some marbles. Stand over the dish of flour and take turns dropping marbles into the flour. (This may be messy, so be careful where you do the experiment.) Retrieve the marbles after every couple of impacts, taking care not to mess up the flour with your fingers or obliterate any "craters." Keep track of how many marbles have been dropped and how many craters you can identify. See how long it takes to reach crater saturation.
