Pilot yearFree, grades 9–12
The Inquiry Atlas
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Student handout

Where the Earth Leaks Heat

What can the surface of the land tell us about the energy beneath it, and what should we do with what we find?

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The photographs

  1. A tall white column of water and steam erupts from a low pale mound and rises through most of the frame against a deep blue sky, its top spreading into a broad billowing cloud that drifts to the right. Inside the column a narrower, denser jet of water is visible, textured and streaked. The mound at its base is bare gray and tan, streaked with runoff, carrying small patches of snow, with thin steam rising from vents to its right. Flat unbroken snow covers the foreground and the middle distance. A dark band of snow-dusted conifers runs along the right horizon, and a pale hazy ridge lies low on the left.
    Photograph 1
  2. Looking straight down at shallow clear water over a floor of dark rust, brown and olive, densely covered in small rounded lumps a centimeter or two across. Along the right side and top right a broad crust rises out of the water in overlapping scalloped lobes, pale gold and mustard at its outer edge and chalky gray-brown on its upper surface, with a few small bright white patches. Left of center an isolated oval of the same crust sits in the water, ringed by a raised gold lip and filled with a smooth pale gray-brown floor, joined to the larger mass at right by a narrow neck. A pocket of water at top right reads dark green. Nothing in the frame gives scale.
    Photograph 2
  3. Looking down on a shallow runoff channel. A vivid orange and gold band roughly a meter wide runs from top to bottom of the frame. It is bordered by crusted white and pale gray mineral deposit, and beyond that by flat brown and tan ground. Small white nodules line the channel edges. A single clump of dry grass sits at left.
    Photograph 3
  4. A wide view. In the middle distance a broad pool of pale blue-green water steams heavily, with a low bank of white vapor drifting across it. In front of the pool the ground is covered in bands of orange, rust and brown microbial mat, cut by darker channels and shallow standing water that reflects the sky. Behind the pool a forested hill rises under blue sky with scattered cumulus cloud.
    Photograph 4
  5. A near-vertical view of a broad microbial mat in shades of tan, brown and orange, covered by a thin sheet of water. Dozens of dark narrow channels branch downhill across the frame in a pattern resembling tree roots or river tributaries. Beyond the mat, a steaming blue pool and a forested hill are visible under a blue sky.
    Photograph 5
  6. An oval hot spring set in flat gray gravel. The near half is a funnel-shaped opening with ribbed yellow-green walls dropping into dark green water at the center. The far half is a shallow shelf covered in orange and mustard-colored mat under clear water. A thin crust of white mineral rims the whole pool. Sparse dry grass grows at the edges.
    Photograph 6
  7. A wide view of white and pale gray terraces built in overlapping ledges, with steam rising in the middle distance. Several bare dead trees stand upright in the terrace, trunks gray and branches broken. Two short blackened stumps stand in the foreground. Mountains and blue sky fill the background.
    Photograph 7

01. Setting the stage

You already know what the tall white column is. Look at the ground instead. One part of it is not doing what the rest of the ground is doing — find it, and tell me why.

02. Engaging with the story

Keep a running list of every material you can identify. Not what you think is happening. Just the stuff: rock, water, vapor, deposits, color, anything alive, anything built by people.

03. Working the evidence

Observe (5 minutes). Record only what is visible. No explanations yet.

  • What do you notice first?
  • What materials, textures and colors can you see?
  • How is the scene arranged? What is near, what is far?
  • Look again for a full silent minute. What did you miss?

Reflect (6 minutes). Now generate and test explanations.

  • What do you think is happening here?
  • What would have to be true underground for this to appear at the surface?
  • The orange runs down the middle and fades outward. What could make a color do that?
  • Compare photograph 3 with photograph 6. Same basin, twenty minutes apart. Why do they look so different?
  • What is missing from these images?

Question (4 minutes).

  • What do you wonder about: who, what, when, where, why, how?
  • Standing there with any instrument you wanted, what would you measure first?

04. Delving deeper

Read all three tables before you answer anything.

Table 1. What different geothermal power plants require
Plant typeReservoir temperature requiredHow it worksWhere it stands in the US
Dry steamAbout 400°F to 650°F (204°C to 343°C)Steam from the reservoir turns the turbine directlyKnown at only two US locations: The Geysers in California and Yellowstone. Only The Geysers operates.
Flash steamAbout 400°F to 650°F, with water above roughly 360°FPressurized hot water flashes to steam as it rises. The steam drives the turbine.The most common existing type in the US.
Binary cycleAbout 200°F to 330°F (93°C to 166°C)Geothermal water heats a second fluid with a lower boiling point. That fluid drives the turbine.Nearly 90 percent of the 735 MW of US capacity built since 2000.
Table 2. US geothermal electricity, 2025
MeasureValue
Total generationAbout 16 billion kilowatt-hours
Share of US utility-scale electricityAbout 0.4 percent
States with geothermal plants7
CaliforniaAbout 69 percent of US geothermal generation
NevadaAbout 25 percent
UtahAbout 3 percent
Table 3. What the law says about this place
YearLawWhat it does
1970Geothermal Steam ActNo geothermal leasing inside national parks
1988Geothermal Steam Act AmendmentsBlocks leasing in the Island Park area outside Yellowstone, and requires protection of designated “significant thermal features” in 16 park units
OngoingBLM regulations, 43 CFR 3200No leases where operations are likely to cause significant adverse effects to those features

05. Reflecting and projecting

Part A. Read the evidence. Based on the photographs alone, what can you conclude about the heat and water beneath this place, and what can you not conclude?

Part B. Make the call. A member of Congress proposes opening a portion of the land just outside Yellowstone to geothermal leasing. Should it happen?

  • Your claim. State your position in one or two sentences.
  • Your evidence. At least two specific observations from the photographs, plus one item from Tables 1, 2 or 3. Name the source of each.
  • Your reasoning. Explain the scientific and practical principles that connect your evidence to your claim.

Students may submit as a written paragraph, a recorded verbal explanation, an annotated photograph, or a labeled diagram. All four are acceptable and the rubric applies equally.

06. Take action

Choose one.

  1. Your state’s heat. Does your state generate geothermal electricity? Where are its heat resources mapped? If it has none, find the nearest state that does and what makes it different.
  2. The Utah question. Companies in Utah are building enhanced geothermal projects that do not rely on natural hot springs at all. They drill into hot dry rock and create the fractures themselves. Research one. What problem does it solve, what are people worried about, and does it change your answer to question 6?
  3. What else is protected. Sixteen National Park Service units have designated significant thermal features. Find another one. What is protected there, and what would be lost if it were not?

07. The rebuttal

Your rebuttal. Someone reaches the opposite conclusion from the same evidence. State their position as fairly as you can, then explain why the evidence favors yours. If you think the evidence does not settle it, say so and explain what would.

Discussion questions

  1. What is the white and gray crust in photograph 3, and where did it come from?
  2. The steam is not smoke and nothing is burning. What is rising, and what made it change from liquid to gas?
  3. Why is the orange brightest in the middle of the channel and faded at the edges?
  4. Photograph 7 was taken twenty miles north of the geyser basins and looks completely different. The white there is calcium carbonate, not silica. What does that tell you about the rock underground in the two places?
  5. Binary cycle plants work at much lower temperatures than flash plants, and almost all new US plants are binary. Why would a company choose the design that produces less power per plant?
  6. Open question. Yellowstone is one of only two known dry steam resources in the country, and it is illegal to develop. Was that the right call?

Photography: Greg Smith. The Inquiry Atlas, a project of The Method Project.

Free to print and use with your classes. Wider reuse terms are still being finalised — please do not republish or redistribute it beyond your own students yet.