Explore! Life on Mars

Mars by the Book

Adapted from Imaginary Martians, Destination: Mars, NASA Johnson Space Center, 2002 and Earth, Earth’s Moon, Mars Balloons, Follow Your Curiosity:  A 2012 NASA Summer of Innovation Collection, NASA JPL, 2012.


In this 30–45-minute activity, children ages 8–13 investigate how Mars compares to the Earth, working together to create an Earth-Mars Comparison Poster to post in the program facility/library and share with their community. Their poster will feature basic facts about Mars and the Earth, as well as a scale model using balloons to represent the two planets.

What's the Point?

  • Earth and Mars have many differences and many similarities.
  • Scientists have gained a great deal of information about Mars in recent years, and there is still much to learn.
  • Our understanding of Mars has changed over time and that change is communicated through nonfiction books.
  • To share our current understanding of Mars with the community through the local library’s circulation (if applicable).
  • Models — such as the children are using here — can be tools for understanding the natural world.
Tips for Engaging Girls in STEM:
  • Provide engaging informational and narrative texts. This activity provides an opportunity for facilitators to leverage their local library (nonfiction) resources and provides book suggestions for engaging the children.


For the group:

  • markers or colored pencils
  • 1 large piece of poster paper or butcher paper
  • 1 red balloon
  • 1 blue balloon
  • 1 piece of blue string or yarn 25 inches long
  • 1 piece of red string 13 inches long
  • 3–4 packages of sticky dots (small round labels)
  • 1 copy of the Earth Fact sheet (per child)
  • selection of nonfiction books about Mars (refer to the resources section for other suggestions)
  • optional:  white board or poster paper and markers or chalkboard and chalk to record the children’s ideas

For each child:

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

For the facilitator:


  • Review the activity procedures and background information about Mars.
  • Prepare an area large enough for the children to be comfortably seated as a group.
  • Prepare the measuring strings/yarn, making sure that they are the correct length.
  • Optional:  Make copies of the Scientist Spotlight pages or Trading Cards


1. Welcome the children and tell them that today they will be discovering facts about Mars through books and comparing Mars to Earth. They will then use their new facts to create an Earth-Mars comparison poster to be displayed in the library/facility following the program. Warm up their minds with a few questions before diving into the activity:

  • What do you think it is like on Mars?
  • How do you think that Mars compares to Earth? How is it similar? Different?

Note: There should be no right or wrong answers at this point. The purpose of this discussion is to see what they think, not whether it is accurate. The facilitator should revisit any misconceptions revealed here during and at the conclusion of the activity.

2. Invite the children to read about Mars! Consider dividing the children into smaller groups, or inviting older children to take turns reading to the group.

  • Have the children read nonfiction books about Mars, and ask them to start writing down interesting or important facts that they find on their piece of scratch paper. Give them about 10–15 minutes to find facts about Mars.

3. Assemble the children in a group and invite them to share what they know about Mars. Hand out the Earth Facts sheet and ask them to compare their findings about Mars to the Earth.

  • How do your findings (about Mars) compare to what you originally thought? Did you learn anything new or surprising?
    Note:  This is an opportunity to correct any incorrect assumptions and misconceptions that the children may have expressed about Mars during the opening discussion.
  • What does Mars look like? Show a picture from one of the books.
  • What color is it?  Red, orange, brown, etc.
  • Is it smaller, larger, or about the same size as Earth?  Smaller!
  • Is it closer or farther from the Sun than Earth?  Farther!
  • What would it be like to live on Mars? Are there mountains? Rivers? Forests?  No, it is soil and rock — very dusty. 
  • What is the weather like?  It is very dry, cold, and windy.
  • How might Earth and Mars be alike? Different?  Some similar features are craters and volcanos; similar length of day.  Different length of year, size, gravity, temperature range, etc.
  • Is there life on Mars?  None that we know of — scientists are still studying this!

4. Have the children work together to draw or make a model of Mars and Earth based on their findings, comparing the two planets, on the large poster. You should create a scale model of Earth and Mars using the blue and red balloons respectively.

  • Explain to the children what a model is and how this particular one will be used to represent Earth and Mars. In this case, they will be using balloons to represent the size of Mars relative to the Earth. Note:  Be sure to point out that they will not be modeling the distance, however (how far apart the planets are), although that would be a fun extension.
  • Create a scale model of Earth and Mars using the balloons
    • Earth:  Blow up the blue balloon so that the blue string/yarn (25 inches long) just wraps around the balloon. Tie off the balloon.
      • Attach the balloon to the poster using tape.
      • Write “Earth” on the poster near the balloon or on the balloon.
    • Mars: Blow up (inflate) the red balloon so that the red string/yarn (13 inches long) just wraps around the balloon. Tie off the balloon.
      • Attach the balloon to the poster using tape.
      • Write “Mars” on the poster near the balloon or on the balloon.

5. Create an Earth-Mars comparison poster. Have the children work together to write short facts about each planet on the poster. Short facts may be written on the round labels and then stuck to the appropriate model planet balloon. Longer facts should be written on the poster. Note: The poster should already have the scale-model planet balloons attached before the children start to add the facts.

In Conclusion

Summarize what was discovered about what it is like on Mars, how it compares to Earth, and congratulate the group on a job well done in creating the scale model and comparison poster. Invite the children to share the poster during their visits with family and friends and to explore Mars further by attending future activities (if applicable)!

  • What new things did they learn?
  • Was there anything they learned about Mars that surprised them?
  • What did they find the most interesting about Mars?
  • Would they like to live on Mars? Why or why not?
  • Do they think now that Mars is more like — or different than — Earth?
  • Do they think that there could be (or have been in the past) life on Mars?

Summarize that Mars and Earth are similar, yet unique, and scientists are interested in Mars as a possible place to find life beyond Earth. Future module activities will explore the requirements for life and why scientists consider Mars a good candidate for life elsewhere in the universe! Optional:  Give each child a copy of the Scientist Spotlight pages or Life on Mars? Trading Cards to take home.

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


If desired, extend this reading activity with an art component. Provide a variety of craft materials that may be used to draw or make a model landscape of Mars (for example, clay or Play-Doh®, sand, rocks, colored and/or plain paper, markers, crayons, glitter, pipe cleaners, foil, pom-poms, tape, glue, etc.) inside a box (with no top and one side mostly removed for viewing). When the children are finished reading the nonfiction books, invite them to draw a picture or create a model of the martian landscape using the craft items available.

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