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

Protecting Life: The Martian Challenge

Adapted from Imaginary Martians, Destination:  Mars, NASA Johnson Space Center, 2002, and the Space Radiation unit of Explore:  Health in Space, Lunar and Planetary Institute, 2006.


During this 60-minute activity, children ages 8–13 create their own “martian” using craft materials and UV beads. They will explore how UV radiation from the Sun can affect living things, comparing conditions on Earth and Mars, and then discuss ways in which organisms may protect themselves from UV radiation. They will then take part in a Mars Creature Challenge, where they will change their creature to help it survive harsh UV conditions — like on Mars. They will then test their Mars creatures by subjecting them to different environmental conditions to see how well they “survive” in a martian environment. This investigation will explore shelter and protection as one of life’s requirements and how Earth’s atmosphere protects life from harmful UV radiation.

This activity may be split into a two-part series of activities, 30 minutes each, if needed.

What's the Point?

Tips for Engaging Girls in STEM:

  • Spark initial interest in the topic. In this case, by engaging the children’s natural curiosity, imagination, and interest in alien life, giving them the opportunity to design their own version of a “martian.”
  • Embed activities in interesting contexts. For 8–13-year-olds, use real-world problems like how to change their creature so that it may survive (Part 2 of this activity). Girls are motivated by projects they find personally relevant and meaningful.
  • Allow children to approach the activities in their own way. Girls are motivated when they can approach projects in their own way, applying their creativity, unique talents, and preferred learning styles. This activity allows the children freedom in the design and creation to their “martian.”
  • Use project-based learning, group work, innovative tasks, and technology (i.e., web) to help engage children. Girls enjoy hands-on, open-ended projects and investigations. This activity (particularly Part 2) requires the children to collaborate to complete the survival challenge.
  • Provide opportunities for participants to engage in activities to develop their spatial skills, such as constructing and engineering projects. This activity provides an opportunity for children to design, build, and draw.


For the large group:

For each child:

Activity Part 1:

Activity Part 2:

Sources for UV Beads:

Educational Innovations
Phone:  1-888-912-7474/Fax:  203-229-0740

Steve Spangler Science
Phone:  1-800-223-9080

For the facilitator:


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

Facilitator’s Note:  Radiation and the Electromagnetic Spectrum
Light and heat are part of the spectrum of energy — or radiation — our Sun provides. We can “see” light and we can feel heat. But there are other types of energy that our Sun produces. Much of this energy makes up the electromagnetic spectrum. Light is part of the visible section of the spectrum and heat is part of the infrared section of the spectrum. Radio waves, microwaves, ultraviolet rays, X-rays, and gamma-rays all are parts of the spectrum of electromagnetic energy — or radiation — from the Sun.

Radiation is energy that travels in waves or as particles. Radio waves, microwaves, visible light, and infrared radiation have relatively long wavelengths and low energy. But ultraviolet rays, X-rays, and gamma-rays have shorter wavelengths and higher energy. This shorter wavelength is so small that these wavelengths interact with human skin, and cells, and even parts of cells — for good or for bad!

Our Sun also produces cosmic radiation. Cosmic rays are very high energy, fast-moving particles (protons, electrons, and neutrinos) that can damage DNA, increasing the risk of cancer and causing other health issues. Cosmic rays have such high energy that it is difficult to design shielding that blocks them; cosmic rays do not only come from our Sun, but from other places in our galaxy and universe.

Human Eye Response

The subject of this activity is ultraviolet — UV — radiation. Humans need UV radiation because our skin uses it to manufacture vitamin D, which is vital to maintaining healthy bones. About 10 minutes of Sun each day allows our skin to make the recommended amount of vitamin D. However, too much exposure to UV causes the skin to burn and leads to wrinkled and patchy skin, skin cancer, and cataracts.

On Earth, we are protected by our atmosphere from most UV radiation coming from the Sun. The ozone layer absorbs much of the UV portion of the spectrum (UVB and UVC). Some still gets through (UVA and a bit of UVB). We can protect ourselves completely by covering ourselves with clothing and using sunblock. Our atmosphere protects us from most of the X-, gamma-, and cosmic rays as well.

On Mars there is very little atmosphere to protect living things from UV radiation — or from X-rays and gamma-rays or even more dangerous cosmic rays. Organisms would have to provide their own protection in the form of body changes (adaptations) or sheltered environments (such as underground). These measures would work fairly well for protecting against UV radiation.

The UV-sensitive beads used in this experiment serve as UV radiation detectors. They contain a pigment that changes color when exposed to ultraviolet radiation from the Sun or from UV lights. The intensity of the color corresponds to the intensity of the UV radiation. When shielded from UV sources, or when exposed to light that does not contain UV radiation — such as indoor light bulbs — the beads remain white. The beads are designed for multiple uses and, according to the manufacturers, will change color up to 50,000 times.

Activity - Part 1

1.Have the children describe some characteristics of Mars that might be helpful to life. If you have conducted previous activities, such as Mars by the Book or the Mars from Above activities, remind the children of their discoveries during those activities.

2. Discuss the challenges that living things on Mars would face. Recall the group definition for life and its needs (the four requirements) from previous activities.

3. Introduce the topic of solar radiation. The children may be unfamiliar with UV radiation and its effect on skin; you may need to lead them through the discussion.

4. Introduce some types of life on Earth that survive in extreme (especially cold, dry) environments. Look over the NAI Extremophile Trading Cards. Optional:  Have the children read and look over the extremophile features in the Life on Mars? trading card set or the activity pages. Note: It may also be helpful to have books about extremophiles from your library collection available for the children to browse through.

5. Invite participants to construct their own “martian” — a Mars creature. Explain that their creatures will include radiation detectors (UV beads) that are made from a special pigment that is very sensitive and turns colors when exposed to the ultraviolet rays. Optional:  Hand out the Explore:  Life on Mars? Trading Cards for inspiration. Optional:  Refer the children to the module scientist pages/features.

6. Construct a martian. Have the children design their own creature with a set number of materials that you provide. Encourage them to share their ideas as they build. Optional:  Have the children draw a picture of their creature in their Extreme-O-File activity pages, or have them “create their own” trading card from the module trading card template.

7. When the children finish, ask them what they observe.

8. Ask the children to cover their martian’s radiation detectors with their hands, and then take it outside. Have them stand in the shade and uncover their creature. 

9. Ask the children to cover their martian with their hands again so that no light reaches it. Keep the creature covered for about 2 minutes while the beads change back to white. Use this opportunity to discuss their observations.

10. Let the children now take their martian into the full Sun.

11. Return indoors and continue the discussion.

Facilitator’s Note:  Some children may say light caused them to change, and others may say heat. Remind them of their observations about the beads inside; the beads were white, even though they were in the light of the room. Ask them what happened to their beads when they brought them back inside; the beads changed from a colored state in the Sun back to white in the room light. If it is heat that causes the change, invite the children to hold beads in their fists; the beads do not change color when heated. They can also heat the beads with a hair dryer (carefully!). The cause of the change comes from the Sun; it is from the part of the Sun’s spectrum we do not see or feel directly.

12. Share with the children that with their martian’s help they have demonstrated the effects of the Sun’s ultraviolet rays on objects (and people!) on Earth. Just like it is important for us to protect ourselves from the harmful UV radiation of the Sun, life on Mars also needs protection! Remember, this is one of the requirements for life!

Activity - Part 2:  Mars Creature Challenge

1. Recall the concept that Earth’s atmosphere protects us from ultraviolet radiation.

Explain that Earth’s atmosphere protects us from many of the dangerous types of radiation from our Sun — ultraviolet radiation, X-rays, gamma-rays, and very high energy cosmic rays. We know that some ultraviolet radiation still gets through (you observed that during Part 1 of this activity), but we can protect ourselves by covering up, limiting our time in the Sun, and using sunscreen. We are going to take what we’ve learned about Mars to help protect our martians!

2. The Creature Challenge:  Invite the children work together in small groups (of 4–6) to protect their creatures from the harsh UV conditions on Mars. The children may modify their creature itself (changing it to the environment) or create a shelter for protection. Ask them to choose one of these options for the challenge. They should make sure that they are able to look inside or hold up and see their UV beads on their creature for the outdoor testing. Encourage the children to share ideas and plan their modifications among their group. Optional:  They may use the Extreme-O-File: Protecting Life activity page to help as they design and plan. Optional:  Have the children draw a picture of their design in their Extreme-O-File activity pages.

3. As a large group, have the children share their creatures and observations.

4. Optional:  Invite the children to consider any other features from which their Mars creatures might need to protect themselves, like the dry and very cold martian environment. They can perform fun tests at home such as having their creature spend the night in a baggie in the freezer, etc.

In Conclusion

Summarize the results of the challenge and what they have learned about ultraviolet radiation on Earth and in space. What helps protect Earth from most of its harmful effects? The atmosphere! How is ultraviolet radiation a challenge to life on Mars and other planets? Recall the requirements for life — particularly protection. What do you think are some ways for living things to protect themselves from UV radiation? What happens to organisms — and children — who receive too much UV radiation?

Facilitator’s Note:  NASA Mission Connection
Radiation Assessment Detector (RAD) for Mars Science Laboratory
This instrument, shown prior to its September 2010 installation onto NASA’s Mars rover Curiosity, will aid future human missions to Mars by providing information about the radiation environment on Mars and on the way to Mars. The results may also help scientists to understand the implications for life there. In November 2012, early results showed a connection between impinging cosmic radiation with weather phenomenon on Mars. For more details, please visit MSL- RAD Science Reports.


Credit:  NASA JPL.