Article
DEVLIN GANDY
Earth and Space,

Secrets of the Boiling River

Scientists investigate a scalding-hot waterway deep in the Amazon rainforest.

By Barbara Fraser & Maggie Mead
From the September 2022 Issue

Learning Objective: Students will describe important traits of an unusual river.

Lexile: 840L; 560L
Guided Reading Level: S
Focus Area: Earth's Waters, Structure & Function,
Standards
  • NGSS: ESS2.A, ESS2.B ELA: Reading Informational Text: 3 TEKS: Science: 3.3B, 4.3B, 5.3B, 6.10A ELA: 3.7C, 4.7C, 5.7C, 6.6C

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  • 840L
  • 560L
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560L
World map showing Peru, the Boiling River, and the Amazon Rainforest

JIM MCMAHON/MAPMAN

An unusual waterway winds through part of the Amazon rainforest in Peru. This river’s water is hot—dangerously hot. In some spots, it reaches nearly 100°C (212°F). That’s water’s boiling point, the temperature at which it turns to gas.

The Boiling River is well-known to locals, who call it Shanay-Timpishka (shah-NIGH teem-PEESH-kah). But scientists are still learning about it. In 2019, a research team set out to explore the river. The team was led by Rosa Vásquez Espinoza, a scientist who studies tiny living things called microbes. Microbes can survive in all types of environments, some even in extreme conditions. The team wondered: What microbes could they find in the Boiling River? 

Hot Water

Underwater image of the Boiling River and its various bubbles

DEVLIN GANDY

Bubbles of water vapor can be seen beneath the river's surface.

The Boiling River flows for 6 kilometers (4 miles) before linking to waterways that feed into the Amazon River. At its start, the Boiling River is 21°C (70°F), room temperature. Downstream, the river flows over faults, deep cracks in Earth’s crust. Water seeps underground, where temperatures are hotter than at the surface. The water heats up. Pressure then forces the hot water up into the river.

There are other spots where hot water spews from Earth. But most are found near volcanoes, where magma, or molten rock, heats water underground. The Boiling River is 700 km (430 mi) from the nearest active volcano. “The fact that it is not volcanic— and so massive—is very unusual,” says Andrés Ruzo. He’s a geologist who is studying how Earth heats the river. 

Two scientists in a lab collecting microbes

LEISA THOMPSON

Rosa Vásquez Espinoza analyzes microbes from the river in her lab. 

Extreme Life

Vásquez’s team collected many samples along the river. They wore protective equipment to scoop water and sediment so they didn’t get burned. The team also gathered soil and scraped microbes off rocks.

Vásquez noted where each sample came from, the water temperature, and the plants and rocks nearby. The team took the samples to a lab to analyze.

The samples contained a trove of microscopic creatures! Vásquez is now studying the role they play in their environment. She and Ruzo hope their work encourages people to save the rainforest. “This research could help us come up with strategies to protect the jungle,” says Ruzo. 

The Amazon’s Boiling River
Watch a video about the Boiling River.

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Step-by-Step Lesson Plan
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1. ENGAGE: Watch a video about an extremely hot river and compare the waterway with typical rivers.

  • Ask students what mental pictures and ideas they associate with the word river. (If needed, share a photo of a river.) Have students record and draw their ideas about rivers before they share with the class. Ask whether any of them have waded into a river. If so, how did the water feel? (e.g., rushing, slowly moving, deep, shallow, cold) 
  • Tell students that they’re going to learn about an unusual river. Play the video “The Amazon’s Boiling River.”  At the 30-second mark, pause the video and discuss the temperature graphic. (The spectrum at right is a key.  The number in that visual’s upper left corner is in degrees Celsius.) Explain that 100° C is water’s boiling point.  Ask students to compare this river’s characteristics with the ideas they had earlier about rivers. Ask: What do you think makes the river so hot?

2. EXPLORE: Read and discuss details from the article.

  • Read the article aloud. Pause and discuss details about what makes the Boiling River unique. Reread the first paragraph under the subheading “Hot Water” (p. 12). Then sketch out how the water gets heated to help students visualize what’s happening to make the river hot. 

3. EXPLAIN: Summarize the article and ask questions about the Boiling River.

  • Ask students to turn to a partner and share the article’s main idea—what it is mostly about. (The Boiling River is an unusual river that scientists are studying.) Discuss their ideas as a class, including details that support the main idea (e.g., the river is very hot but not near a volcano). Distribute Read and Review to students and complete the first part together. Then have students complete the rest independently or with a partner.
  • Have students share their questions from the last prompt on the Read and Review skills sheet. Discuss where they could find answers to their questions. If time allows, have students use reputable sources to find answers.

4. EXTEND: Interpret a map of South America and its biomes.

  • Preview the Biomes of South America map skills sheet. If you have a world map, work with students to locate South America. Briefly talk about the characteristics of the terrestrial biomes. (See the biome descriptions on the following page.) Have students complete the skills sheet with a partner. As a bonus, ask students which biomes are not represented on the map. (The word land is a hint—the ocean has biomes too, but those are not marked.)

5. EVALUATE: Reinforce understanding of core ideas with a multiple-choice assessment.

  • Have students reread the article or listen to it using the text-to-speech function (available on the left-hand side of the scrollable online article). Then have them complete the article’s Quick Quiz.

Text-to-Speech