Pilot yearFree, grades 9–12
The Inquiry Atlas
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The Same Shape on Two Planets

What can a shape in the sand tell us about a force we cannot see — and what happens when we loosen the ground it comes from?

Ripples in sand, a stone with one face cut flat, a dune field with a mountain range behind it, and the same forms photographed on Mars. One process, four scales, two planets.

Teacher guideStudent handout
Grades9–10, 11–12
SubjectsEarth Science · Environmental Science
Time15 min · 45 min · 90 min
PreparationLight prep
StandardsHS-ESS2-1 · HS-ESS2-2 · HS-ESS3-1
CostFree

Choose a path

  1. 01

    Setting the stage

    5 min

    Project photograph 1 with no title, no caption and no context. Say nothing about it. Ask one question — “Something made this pattern. What?” — and take four or five answers. Do not confirm or correct any of them. Write the guesses on the board. Then ask a second question and leave it open: “There are faint curved lines in the sand beside the grass. What drew them?”

    A field of pale, near-white sand fills the whole frame, covered in fine parallel ripples a few centimeters apart running in gentle S-curves from the top of the frame to the bottom. Slightly below center sits a single clump of fine grass, its blades fanning out to the right in tan, olive and pale green, with seed heads. Faint curved arcs are scratched into the sand to the left of the clump. Just below it a low plant with gray-green oval leaves carries several clusters of small bright purple flowers, casting sharp shadows to the left. The light is low and comes from the right.
    Pale sand, ripple after ripple, and one clump of grass. Look at the ripple spacing — it is regular, and it changes where the grass sits. Look at the faint curved lines scratched into the sand beside the clump. Something drew them. The lesson starts by asking what. Provisional caption — not yet confirmed by the photographer
  2. 02

    Engaging with the story

    10 min

    Show photographs 2, 3 and 5 — not 4 yet. Give students a job before you start. If Greg’s field account has been recorded, read it aloud while the images are on screen. If it has not, give students a silent minute with each frame instead.

    The inside of a narrow, deep canyon in orange and red sandstone, photographed looking upward. The walls curve and fold around the frame in smooth, rounded, layered surfaces, banded light and dark along the bedding, with no sharp edges. At the top center a narrow gap opens to a bright white sky. A single beam of light angles down from that gap through the middle of the frame, and fine particles are visible falling and drifting within it. The lower left of the frame is hazy with suspended dust; the right-hand walls are lit warm orange.
    A narrow canyon in orange rock, its walls smooth, curved and layered like something poured rather than broken. A single shaft of daylight comes in from a gap far above, and fine particles are falling through it. Two very different forces could have shaped this. Deciding which is the work. Provisional caption — not yet confirmed by the photographer
    A patch of fine red-orange desert sand seen from above, scattered with pebbles and small stones of many colors — gray, blue-gray, pink, tan, black — from a few millimetres to a few centimetres across, most of them rounded. Slightly above center lies a single larger stone about ten centimeters long: a conglomerate of pebbles set in a matrix, with one broad, smooth, flat pale gray face occupying most of its upper surface and a sharp boundary where that face ends. It casts a long shadow to the lower left. In the top right corner is a small clump of dry pale grass.
    Red sand, scattered pebbles, and one stone that is not like its neighbours: a smooth, flat, pale gray face, sharply bounded, on a rock that is otherwise rounded and knobbly. The neighbours are rounded. This one has been cut. Provisional caption — not yet confirmed by the photographer
    A wide panorama. The lower third is flat grassland and a line of green cottonwood trees. Behind them rises a field of smooth tan sand dunes, layered one behind another, their crests running in long sinuous lines and their flanks in light and shadow; two or three tiny dark specks on one crest at the left appear to be people. Behind the dunes a steep mountain range rises abruptly, dark green with conifer forest on its lower slopes and bare gray rock with a dusting of snow on the summits. A broad blue sky with streaked and puffy white cloud fills the top half.
    The same process, at the largest scale it reaches on this planet. A field of dunes hundreds of meters high, with a mountain range standing immediately behind it. Ask students why the sand stopped here, of all places — the answer is in the mountains. Provisional caption — not yet confirmed by the photographer
  3. 03

    Working the evidence

    15 min

    The core of the investigation. Students work in pairs on the handout, using the Observe, Reflect, Question structure the Library of Congress developed for reading primary sources. Put photograph 1 back on screen and leave it there.

    A field of pale, near-white sand fills the whole frame, covered in fine parallel ripples a few centimeters apart running in gentle S-curves from the top of the frame to the bottom. Slightly below center sits a single clump of fine grass, its blades fanning out to the right in tan, olive and pale green, with seed heads. Faint curved arcs are scratched into the sand to the left of the clump. Just below it a low plant with gray-green oval leaves carries several clusters of small bright purple flowers, casting sharp shadows to the left. The light is low and comes from the right.
    Pale sand, ripple after ripple, and one clump of grass. Look at the ripple spacing — it is regular, and it changes where the grass sits. Look at the faint curved lines scratched into the sand beside the clump. Something drew them. The lesson starts by asking what. Provisional caption — not yet confirmed by the photographer
  4. 04

    Delving deeper

    10 min

    Now name the mechanism: wind moves material three ways — suspension, saltation and creep — and grain size decides which. Give them the one-centimeter figure and let it land. Then show photograph 4 for the first time and say only, “This one was taken on Mars.” Give it a moment. Then hand out the data.

    An overhead view of a surface covered in dark, elongated dune forms arranged in roughly parallel rows running from the upper left to the lower right, each dune rounded at one end and tapering at the other. Between and around them the ground is pale gray and pinkish-tan with a lumpy, blotchy, quilted texture. Fine ripple lines are visible on the smooth tan surfaces between the dunes. There is no sky, no horizon and no object of known size anywhere in the frame.
    The same forms, on another planet. Dark dunes march in rows across pale ground near Mars’s permanent polar cap. The air here is about one percent as dense as the air at sea level on Earth. Nothing about the shapes tells you that. Provisional caption — not yet confirmed by the photographer
  5. 05

    Reflecting and projecting

    15 min

    The claim, evidence and reasoning assignment. Two parts. Both appear on the student handout as Part A and Part B.

The evidence

A field of pale, near-white sand fills the whole frame, covered in fine parallel ripples a few centimeters apart running in gentle S-curves from the top of the frame to the bottom. Slightly below center sits a single clump of fine grass, its blades fanning out to the right in tan, olive and pale green, with seed heads. Faint curved arcs are scratched into the sand to the left of the clump. Just below it a low plant with gray-green oval leaves carries several clusters of small bright purple flowers, casting sharp shadows to the left. The light is low and comes from the right.

Pale sand, ripple after ripple, and one clump of grass. Look at the ripple spacing — it is regular, and it changes where the grass sits. Look at the faint curved lines scratched into the sand beside the clump. Something drew them. The lesson starts by asking what.

Location not yet confirmed · Greg Smith

Provisional caption — not yet confirmed by the photographer

The inside of a narrow, deep canyon in orange and red sandstone, photographed looking upward. The walls curve and fold around the frame in smooth, rounded, layered surfaces, banded light and dark along the bedding, with no sharp edges. At the top center a narrow gap opens to a bright white sky. A single beam of light angles down from that gap through the middle of the frame, and fine particles are visible falling and drifting within it. The lower left of the frame is hazy with suspended dust; the right-hand walls are lit warm orange.

A narrow canyon in orange rock, its walls smooth, curved and layered like something poured rather than broken. A single shaft of daylight comes in from a gap far above, and fine particles are falling through it. Two very different forces could have shaped this. Deciding which is the work.

Location not yet confirmed · Greg Smith

Provisional caption — not yet confirmed by the photographer

A patch of fine red-orange desert sand seen from above, scattered with pebbles and small stones of many colors — gray, blue-gray, pink, tan, black — from a few millimetres to a few centimetres across, most of them rounded. Slightly above center lies a single larger stone about ten centimeters long: a conglomerate of pebbles set in a matrix, with one broad, smooth, flat pale gray face occupying most of its upper surface and a sharp boundary where that face ends. It casts a long shadow to the lower left. In the top right corner is a small clump of dry pale grass.

Red sand, scattered pebbles, and one stone that is not like its neighbours: a smooth, flat, pale gray face, sharply bounded, on a rock that is otherwise rounded and knobbly. The neighbours are rounded. This one has been cut.

Location not yet confirmed · Greg Smith

Provisional caption — not yet confirmed by the photographer

An overhead view of a surface covered in dark, elongated dune forms arranged in roughly parallel rows running from the upper left to the lower right, each dune rounded at one end and tapering at the other. Between and around them the ground is pale gray and pinkish-tan with a lumpy, blotchy, quilted texture. Fine ripple lines are visible on the smooth tan surfaces between the dunes. There is no sky, no horizon and no object of known size anywhere in the frame.

The same forms, on another planet. Dark dunes march in rows across pale ground near Mars’s permanent polar cap. The air here is about one percent as dense as the air at sea level on Earth. Nothing about the shapes tells you that.

Mars, near the north polar cap — 73.993°N, 288.300°E · NASA/JPL-Caltech/Univ. of Arizona

Provisional caption — not yet confirmed by the photographer

A wide panorama. The lower third is flat grassland and a line of green cottonwood trees. Behind them rises a field of smooth tan sand dunes, layered one behind another, their crests running in long sinuous lines and their flanks in light and shadow; two or three tiny dark specks on one crest at the left appear to be people. Behind the dunes a steep mountain range rises abruptly, dark green with conifer forest on its lower slopes and bare gray rock with a dusting of snow on the summits. A broad blue sky with streaked and puffy white cloud fills the top half.

The same process, at the largest scale it reaches on this planet. A field of dunes hundreds of meters high, with a mountain range standing immediately behind it. Ask students why the sand stopped here, of all places — the answer is in the mountains.

Location not yet confirmed · Greg Smith

Provisional caption — not yet confirmed by the photographer