"Liquid water is an essential requirement for life, and liquid water serves as a kind of surrogate indicator for biological activity. The element iron interacts strongly with liquid water, especially with water in which gases like CO2 and O2 are dissolved."
"Therefore: The history of water on Mars is reflected in the iron mineralogy of the Martian soil, a soil colored red by Fe3+-compounds. Fe3+-ions are essential ingredients in all naturally occurring magnetic compounds. From the brief description given below it will become apparent that the investigation of the magnetic phase in the Martian soil is strongly coupled to the study of the history of water on the surface of the planet.'
Exercises include: (1) modeling the surface using the maps and "rock" files, (2) making qualitative estimates of the strengths of the "soils or dirts" at the landing sites, and (3) interpreting Viking lander images. In one exercise, students locate "Mr. Toad" (of Wind in the Willows fame) in images and on a map. Maps, images, and instructions are provided for the exercises.
The exercises are structured so that they can be used by a broad range of students.