Rocks and Minerals on Mars

Overview

Students investigate rocks and minerals on both Earth and Mars. Through hands-on sorting, observation with magnifying glasses, and a rust-making demonstration, students discover why Mars is red and learn how robotic geologists study Martian rocks from millions of miles away.

Background for Teachers

Mars is a rocky planet with a geology shaped by volcanism, impact cratering, and wind erosion. The distinctive red color comes from iron oxide (rust) in the regolith (surface soil). Mars rovers like Curiosity and Perseverance act as robotic geologists, analyzing rocks with cameras, spectrometers, and drills. Key minerals found on Mars include:

• Hematite — iron oxide mineral; found as “blueberries” (small spherules) by the Opportunity rover
• Basalt — volcanic rock that makes up much of the Martian surface
• Olivine — a green mineral found in volcanic rocks on both Earth and Mars
• Clay minerals — evidence that liquid water once existed on the surface

Lesson Procedure

Warm-Up (10 minutes)

1. Display images of Earth landscapes alongside Mars surface photos from NASA rovers.
2. Ask: “What do you notice about the ground in both pictures?”
3. Introduce the idea that both Earth and Mars are rocky planets made of similar materials.

Rock Observation Station (20 minutes)

Set up stations with labeled rock samples:

Station 1: Basalt

• Dark, fine-grained volcanic rock
• “This rock formed from a volcano — both Earth and Mars have lots of basalt!”

Station 2: Hematite (Iron Ore)

• Reddish-black, heavy mineral
• “This mineral is full of iron. Mars has so much of this that the whole planet looks red!”

Station 3: Sandstone

• Layered, gritty texture
• “This rock formed from layers of sand pressed together. Curiosity rover found sandstone on Mars!”

Station 4: Quartz/General

• Various colors, glassy
• “Minerals come in many colors and textures. Scientists sort rocks just like you are doing!”

Students rotate through stations, using magnifying glasses to observe each rock. They record observations on their worksheet: color, texture (rough/smooth), weight (heavy/light), and which rocks they think might be found on Mars.

Demonstration: Making Rust (10 minutes)

1. Show students iron filings (or steel wool).
2. Explain: “Iron is a metal found in rocks. When iron meets water and air, it turns into rust.”
3. Show a pre-prepared sample of rusted iron (or demonstrate by wetting steel wool and observing color change over days).
4. Connect: “Mars has LOTS of iron in its soil. Billions of years ago, when Mars had water, the iron rusted — and that is why Mars is the Red Planet!”

Rovers as Rock Scientists (10 minutes)

1. Show images of Curiosity and Perseverance rovers.
2. Explain that rovers have tools just like geologists: cameras (eyes), drills (to look inside rocks), and special instruments that can tell what minerals are present.
3. Show a close-up image of a rock studied by a rover. Ask: “What do you observe?”
4. Discuss: “When scientists send humans to Mars, they will be able to pick up rocks and study them with their own hands!”

Wrap-Up (10 minutes)

1. Students share their favorite rock from the stations and explain why.
2. Review: “Why is Mars red?” (Iron oxide / rust in the soil)
3. Preview: “Scientists found clues in the rocks that Mars once had water. Next time we will explore where that water went!”

Assessment

• Formative: Rock observation worksheets with accurate descriptions of properties
• Discussion: Students can explain why Mars appears red
• Exit ticket: Draw a picture of a rover studying a rock on Mars and label one thing the rover might discover

NGSS Alignment

• 2-ESS1-1: Use information from several sources to provide evidence that Earth events can occur quickly or slowly
• 2-PS1-1: Plan and conduct an investigation to describe and classify different kinds of materials by their observable properties

Extensions

• Set up a long-term rust experiment: place iron objects in wet and dry conditions, observe over 2 weeks
• Create a class “Mars Rock Museum” with student-made labels for each sample
• Watch NASA JPL video of Perseverance rover collecting rock samples
• Read If You Decide to Go to the Moon by Faith McNulty (space exploration connection)