Education and
Public Engagement
at the Lunar and Planetary Institute
Explore! Life on Mars

Mars from Above: Carving Channels

Adapted from selected activities from Mapping Mars, Destination:  Mars, NASA Johnson Space Center, 2002, and the Scratching the Surface unit of Explore! Mars:  Inside and Out, Lunar and Planetary Institute, 2007.


Carving Channels is a 15-minute activity in which children ages 8–13 create channel features with flowing water, comparing their observations to real images of Mars and Earth taken by satellites/orbiters. Their observations of the ways in which flowing water alters the surrounding terrain are used as clues to draw conclusions about Mars’ geologic past and its ability to support life, as well as how scientists view these features from space.

What's the Point?

Tips for Engaging Girls in STEM:

  • Use group work and collaboration to help engage children. Girls benefit from collaboration, especially when they can participate and communicate fairly. This activity gives the children the opportunity to collaborate and work together in a fun and engaging social environment.
  • Encourage critical thinking. Girls gain confidence and trust in their own reasoning when encouraged to think critically. This activity provides an opportunity for children to use imagery to think critically about what it is like on Mars (what we can observe) and what that can tell us about its past and potential to support life — now or in the past.
  • Provide opportunities for developing spatial skills. Spatial skills are not innate and can be improved with training and experience. This activity provides an opportunity for children to think three-dimensionally, by creating a model and drawing to represent their ideas.


The following materials are for this activity conducted as stations.

For each station: The following materials will serve approximately 8 children working in teams of 3–4. Two “stream tables” are recommended (one per team) for this station, as listed below:

Earth Image Placemats (large file, 23 MB)
Earth Image Placemats (small file, 3 MB)

Mars Cards (large file, 14 MB)
Mars Cards (small file, 2.8 MB)

Facilitator’s Note: Sand and diatomaceous earth can be dried out and reused!

Caution:  Diatomaceous earth poses an inhalant hazard and can cause eye irritation if handled improperly. If you choose to use it in your stream tables, set up the stream tables beforehand and keep the diatomaceous earth moist or covered to keep it from becoming airborne in the presence of children. Use caution when working with the diatomaceous earth and setting up the tables. You may use a mask to protect yourself. It is also a good idea to wear gloves when handling this material as it may dry hands significantly.

For each child:

Trading Cards (large file, 34 MB)
Trading Cards (small file, 7 MB)

For the facilitator:



1. Consider the images of channels on Mars and Earth. Explain that these images were taken by spacecraft looking down on the planets.

Facilitator’s Note: Early Mars was wetter and warmer. Several lines of scientific evidence support this claim. Images obtained by Mars orbiters have revealed that the ancient southern highlands are covered by dendritic drainage patterns  networks of stream channels, or “valley networks” that erode into the highland craters. While there are some differences, these features are generally similar to the networks of gently meandering river channels on Earth. The valley networks on Mars are interpreted to have formed slowly, and thus they require a time in martian history when flowing liquid water was stable at or near the surface of the planet. Chemical measurements made from orbit reveal the presence of clay associated with some of these channels; the formation of clay requires that water was present at some time. Additional evidence for liquid water was found by the Mars Exploration Rovers. They documented structures in the rocks that are created by flowing water, and minerals formed in salty, acidic water.

2. Point out that the trays and their contents are called stream tables, and they contain sand (and possibly diatomaceous earth).

3. Invite the children to create their own channels! Invite the children to take turns holding a water bottle at the high end of the tray and slowly pouring water, gently and steadily, into each tray.

4. Discuss what the model means in terms of Earth and Mars. Explain that both Mars and Earth have features that look like meandering channels (look at the Mars Match Cards and Earth Image Placemats). Mars also has some features that look like the braided channels and teardrop-shaped islands. We know that features like these are formed by water on Earth. This means that it is likely that the channels that we see on Mars were also caused by flowing water. Using these observations, we can recreate an image of what Mars was like in the past!

Mars Cards (large file,14 MB)
Mars Cards (small file, 2.8 MB)

Earth Image Placemats (large file, 23 MB)
Earth Image Placemats (small file, 3 MB)

In Conclusion

Have the children reflect on what they observed and the images from Mars and Earth. Optional:  Invite them to record what they learned and to finish completing the questions in their Extreme-O-Files: Carving Channels activity pages (if they have not already).

Facilitator’s Note: You may want to bring the children’s attention to the fact that the water is no longer present in the channels in the stream table, but the channels are still there — the channel offers evidence that water flowed across the surface in the past. It is also possible that another fluid — other than water  carved the channels. However, there is other evidence on Mars that water is the most likely option  water exists as ice caps near the poles and is suspected to exist in the soil as well.

Summarize that Mars and Earth have been shaped by similar processes, and that we can find stream channels on both planets.