The Atmosphere of Mars

Overview

Earth’s atmosphere is a life-sustaining blanket of gases that we take for granted every day. In this lesson, students compare Earth’s thick, oxygen-rich atmosphere with the thin, carbon-dioxide-dominated atmosphere of Mars. Through data analysis and a design challenge, students understand why human settlement on Mars requires innovative life support technology.

Background for Teachers

Mars has an atmosphere, but it is vastly different from Earth’s:

Mars’s atmosphere is about 100 times thinner than Earth’s. This means:

• Humans cannot breathe the air (almost no oxygen, mostly carbon dioxide)
• Liquid water cannot exist on the surface (too little pressure — water boils or sublimates)
• Less protection from solar radiation and meteorites
• Less heat retention (though CO2 does create a small greenhouse effect)

NASA’s MOXIE experiment on the Perseverance rover successfully produced oxygen from Mars’s carbon dioxide atmosphere, demonstrating technology that future settlers will use.

Lesson Procedure

Warm-Up: The Balloon Demonstration (10 minutes)

1. Hold up two balloons: one fully inflated, one barely inflated.
2. “The big balloon represents Earth’s atmosphere. The small balloon represents Mars’s atmosphere. Mars has an atmosphere, but it is about 100 times thinner than ours!”
3. Ask: “What does our atmosphere do for us?” Collect ideas: gives us air to breathe, keeps us warm, protects us from space, holds in water.

Data Analysis: Atmosphere Comparison (20 minutes)

1. Provide students with simplified data tables showing:

   • Gas composition of each atmosphere (percentages)
   • Surface pressure comparison
   • Temperature ranges

2. Students create two pie charts — one for Earth’s atmosphere, one for Mars’s atmosphere — using colored pencils:

   • Earth: large nitrogen section (blue), significant oxygen section (green), tiny other gases
   • Mars: almost entirely carbon dioxide (red/orange), tiny nitrogen and argon sections

3. Guided analysis questions:

   • “Which gas do we need to breathe? How much of it is in Earth’s air vs. Mars’s air?”
   • “What is the most common gas on Mars?”
   • “Why do you think Mars is so much colder than Earth?” (thinner atmosphere traps less heat)

What the Atmosphere Does for Us (10 minutes)

Create a class chart: “Jobs of an Atmosphere”

Discussion: “When humans settle Mars, they will need to solve every single one of these problems!”

Design Challenge: Life Support for Mars (15 minutes)

Working in pairs, students design a simple concept for a Mars habitat life support system on poster paper:

• How will settlers get oxygen? (Possible ideas: bring it from Earth, make it from Mars air like MOXIE, grow plants)
• How will they stay warm? (Heated habitats, insulation, underground structures)
• How will they protect from radiation? (Thick walls, underground living, water shielding)

Students draw and label their design with at least three features.

Wrap-Up (5 minutes)

1. Two or three pairs share their designs.
2. Review key idea: Mars has an atmosphere, but it cannot support human life without technology.
3. Share: NASA’s MOXIE experiment already proved we can make oxygen from Mars’s air — the technology is being developed right now!

Assessment

• Pie charts: Accurate representation of atmospheric composition for both planets
• Design poster: Includes at least three labeled life support features with explanations
• Discussion: Students can explain at least two reasons humans cannot live on Mars without life support

NGSS Alignment

• 4-ESS2-1: Make observations and/or measurements to provide evidence of the effects of weathering or the rate of erosion by water, ice, wind, or vegetation
• 4-PS3-2: Make observations to provide evidence that energy can be transferred from place to place by sound, light, heat, and electric currents
• 3-5-ETS1-1: Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost

Extensions

• Research MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) and create a poster explaining how it works
• Grow plants in sealed containers to demonstrate how plants convert CO2 to oxygen
• Calculate how much oxygen a person uses per day and how many MOXIE devices would be needed
• Connect to greenhouse effect lessons: compare Earth, Mars, and Venus atmospheres