The Search for Water on Mars

Overview

Water is the key to life as we know it — and finding evidence of water on Mars is one of the most exciting discoveries in planetary science. In this lesson, students examine NASA images showing evidence of ancient rivers and lakes on Mars, then conduct a hands-on erosion experiment to understand how flowing water shapes landscapes on any planet.

Background for Teachers

Multiple lines of evidence indicate that liquid water once flowed abundantly on the surface of Mars:

• Valley networks in the southern highlands resemble river drainage systems on Earth
• Gale Crater (where Curiosity rover operates) was once a lake billions of years ago
• Jezero Crater (Perseverance rover’s landing site) was a river delta where water deposited sediments
• Mineral evidence: clay minerals and sulfate salts form only in the presence of water
• Polar ice caps contain water ice mixed with frozen carbon dioxide

Today, Mars is too cold and its atmosphere too thin for liquid water to persist on the surface. However, water ice exists at the poles, just below the surface in many regions, and possibly as briny (very salty) liquid in some locations. When humans reach Mars, accessing this water will be essential for drinking, growing food, and producing rocket fuel.

Lesson Procedure

Warm-Up (10 minutes)

1. Show an image of a river delta on Earth (such as the Nile Delta from space).
2. Ask: “What made this shape? How does water change the land?”
3. Now show a NASA image of Jezero Crater on Mars. Ask: “Does this remind you of anything?”
4. Reveal: “Scientists believe this was once a lake with a river flowing into it — just like on Earth!”

Erosion Experiment (25 minutes)

Setup: Each group receives a sand/soil tray tilted at a slight angle with small blocks or figures to represent landscape features.

Procedure:

1. Students sketch their “Mars landscape” before adding water.
2. Slowly pour water from the top of the tilted tray using a pitcher.
3. Observe how water flows, creates channels, and moves sediment.
4. Sketch the landscape after water has flowed through.
5. Compare before and after drawings.

Guided Questions:

• “What happened to the sand where the water flowed?”
• “Did the water create any channels or valleys?”
• “Where did the sand that moved away end up?” (at the bottom — like a delta)
• “How does this compare to the Mars images we saw?”

Connection: “Billions of years ago, water did this same thing on Mars. The channels and deltas we see in NASA photos were made by real flowing water!”

Image Analysis (15 minutes)

Display a set of paired images (Earth feature alongside Mars feature):

1. River channels: Earth river vs. Mars valley networks
2. Deltas: Earth river delta vs. Jezero Crater delta
3. Erosion patterns: Earth canyon walls vs. Mars crater walls with gullies

For each pair, students discuss:

• “What similarities do you see?”
• “What differences do you notice?”
• “What does this tell us about Mars’s past?”

Wrap-Up (10 minutes)

1. Discussion: “Why is finding water on Mars so important?”
   • Water is needed for life
   • Water is needed for future human settlers (drinking, farming, making fuel)
   • Water tells us Mars was once warmer and wetter — more like Earth
2. Key vocabulary review: erosion, channel, delta, evidence
3. Students write one sentence in their lab notebook: “Water on Mars is important because…”

Assessment

• Lab notebook: Before/after erosion sketches with labeled observations
• Discussion participation: Students can connect experimental results to Mars features
• Written response: “Water on Mars is important because…” sentence demonstrates understanding

NGSS Alignment

• 3-ESS2-1: Represent data in tables and graphical displays to describe typical weather conditions expected during a particular season
• 3-ESS2-2: Obtain and combine information to describe climates in different regions of the world (extended to compare planetary climates)
• 3-LS4-1: Analyze and interpret data from fossils to provide evidence of organisms and environments in which they lived long ago (connection to searching for evidence of past environments)

Extensions

• Research the Mars Perseverance rover’s mission at Jezero Crater — what has it found so far?
• Create a class timeline showing when scientists discovered evidence of water on Mars
• Design a “Water Finder” tool that future Mars settlers might use to locate underground ice
• Read about how NASA’s MOXIE experiment on Perseverance is testing technology to make oxygen from Mars’s atmosphere