Shadows from craters, images of dunes, and pictures from space are explored by Excel students.

First you make a crater from playdough.

Then you examine the shadows cast and compare with pictures taken by the Clementine space probe.

Lining up to take a picture of a model dune made in a dishpan.

A closeup of the dune.

Importing the picture into NIH Image and changing the palette.

A surface plot of the image done by NIH Image.

Looking at images of the earth on the CDROM Small Blue Planet.