Purpose: First, students pour water into a sand-filled tray to see what kinds of shapes the flowing water makes. Then, students examine images of the Martian surface to see if there are any features that suggest the presence of flowing water.

• Flowing water creates characteristic features that can be used to interpret water flow.
• Most river and stream beds have inclinations below 5 degrees.
• Small, light sediments are carried more easily by flowing water than large, heavy ones.
• Gently-flowing water sorts sediments in predictable, consistent ways.
• Models such as stream tables can represent real-world processes.
• Various Martian landforms seem to support the idea that water flowed across the surface.

Purpose: Students study images of teardrop-shaped landforms on Mars and devise a series of experiments to recreate those shapes as closely as possible.

• The teardrop-shaped landforms at the mouth of Ares Vallis lend strong support to the idea that water flowed on Mars.
• A landform's shape is the result of the interaction of several variables.

Purpose: Students create a model to study a unique Martian landform considered an important source of Mars' past surface water.

• Chaotic terrain is thought to form when the removal of subsurface water or ice causes a loss of support, and the ground collapses under its own weight.
• Areas of chaotic terrain are lower than the surrounding plateau, have irregularly-shaped, variously-sized blocks of crust on the depression floor, and have channels leading away from them.
• Chaotic terrain is considered a source for the fluid(s) that created the channels.

Purpose: First, students study J. Harlen Bretz's work on Earth's greatest flood, the flood that created the Scablands in Washington State. Next, they compare the landforms created by this flood with similar-looking Martian landforms and realize that Mars also experienced tremendous floods in its past.

• There was a tremendous flood that created the Scabland region in eastern Washington.
• Catastrophic floods leave telltale features such as erratics and huge-scaled ripple marks and gravel bars.
• The Scablands serve as an Earth analog to the Martian flood channels.
• Even when a scientist is right, his or her ideas may be ridiculed.

Purpose: Students use a beach or sand-covered driveway to create flood models at a large scale and to see more clearly the features created by an immense flood.

• In order to form, Scabland features required high flow rates and immense quantities of water.
• Features created in the model illustrate features associated with the Scabland flood.
• Larger-scaled models enable one to study the more subtle aspects of a process.

Purpose: Students examine sand samples and realize that sediments can provide information about where they originated and how they were deposited. This awareness helps students understand why Pathfinder landed in a floodplain.

• Sand grains contain clues about their origin and history.
• A sand sample reflects the geology of its watershed or region.
• One of Pathfinder's mission objectives is to gather evidence that will enable scientists to better understand the composition of the Martian crust and the planet's early geologic history.
• The Thermal Emission Spectrometer on the Mars Global Surveyor and the APXS mounted on the micro-rover will enable scientist to determine the abundance of major chemical elements in the rocks and soil near the lander.

Purpose: Students apply what they learned earlier in the module about flooding and consider whether the evidence supports the idea that there were mammoth floods on Mars.

• Many surface features lend strong support to the idea of catastrophic flooding on Mars.
• The fluid that created the channels was probably water.
• Ice, groundwater, or surface lakes may have been the source of the flood water.
• Crater density is a technique for dating he age of a planet's surface.
• Mars Pathfinder has sampled many kinds of rocks deposited during the flooding.

Purpose: Students articulate their Mars-related questions, identify specific information they need to answer those questions, and learn how to access that information.

• The Mars Pathfinder and the Mars Global Surveyor have specific mission objectives and a selection of instruments to help achieve those objectives.
• The intruments and investigations arise out of questions people have about Mars, and students are fully capable of generating questions worthy of future study.
• The Mars Global Surveyor mission has a specific timetable, and students can follow the progress of the mission in a number of ways.