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Water World

In this lesson, students explore the water cycle and where humans live relative to water, learn about Earth’s water distribution, get to know a river or stream in their neighborhood, and think about river travel today and in the past. This lesson is intended for grades 4-6 and is aligned to NGSS.

Classroom Lesson: Water World

In this lesson, students explore the water cycle and where humans live relative to water, learn about Earth’s water distribution, get to know a river or stream in their neighborhood, and think about river travel today and in the past. This lesson is intended for grades 4-6 and is aligned to NGSS.

Grades: 4-6

Topics: Water cycle, rivers, water distribution, watersheds

Length: 5 lessons, 1-3 class periods each


  • Recall or discover that Earth is the “Water Planet”.
  • Develop an understanding of the importance of water to humans and other living organisms.
  • Deepen their understanding of and their connection to the water cycle.
  • Explore their local bodies of water.
  • Understand that the amount of drinkable (not salty, not frozen) water on Earth is very small.
  • Explore the Green and Colorado Rivers as an example of a well-studied river system, including perspectives from people traveling down these rivers in 1869 and in 2019.

Next Generation Science Standards (NGSS) Alignment:

ESS2.A: Earth Materials and Systems: Rainfall helps to shape the land and affects the types of living things found in a region. Water, ice, wind, living organisms, and gravity break rocks, soils, and sediments into smaller particles and move them around. (4-ESS2-1)

ESS2.C: The Roles of Water in Earth’s Surface Processes: Nearly all of Earth’s available water is in the ocean. Most fresh water is in glaciers or underground; only a tiny fraction is in streams, lakes, wetlands, and the atmosphere. (5- ESS2-2)

ESS3.C: Human Impacts on Earth Systems: Human activities in agriculture, industry, and everyday life have had major effects on the land, vegetation, streams, ocean, air, and even outer space. But individuals and communities are doing things to help protect Earth’s resources and environments. (5-ESS3-1)

MSS2.C: The Role of Water in Earth’s Surface Processes: Water continually cycles among land, ocean, and atmosphere via transpiration, evaporation, condensation and crystallization, and precipitation, as well as downhill flows on land. (MS-ESS2-4)

Materials Needed:

  • General: Internet access, online or paper topographic maps (download free USGS topographic maps from the block below), online or paper map of human population density, digital camera, smart phone, or sketching materials such as colored pencils, notebook or online document for recording observations
  • For the optional hands-on experiment in Lesson 2: Clear glass or plastic container, lid for container or plastic wrap, soil, small rocks, water


Lesson 1: Where do people live relative to water? In this lesson, students explore maps and discuss with one another the prevalence of water on Earth’s surface and the tendency of humans to settle near water. Students compare topographic maps with maps of human population density to help them discover that humans live near water. They explore Earth's water distribution and the small amount of liquid freshwater that can be used by humans. Students dig deeper with an interactive map of U.S. rivers in the United States to explore the connectedness of rivers and to introduce them to the concept of watersheds.

Lesson 2: The Water Cycle. Students learn the pathways and reservoirs of the water cycle by creating a model and conducting an experiment. An option for making this a project-based learning lesson that connects with the local watershed is provided.

Lesson 3: Earth's Water Distribution. Earth is known as the Water Planet, but how much of Earth's water is actually drinkable? How much water is in the oceans? How much is ice, in groundwater, and in surface water (lakes, rivers, streams)? This lesson looks at where Earth's water is and how much is salty versus fresh.

Lesson 4: Getting to Know the Colorado River and a River or Stream Near You. This lesson encourages students to make their own observations of a natural water source they are familiar with. Then, students use the USGS Sreamer application to learn where that water comes from, and where the water is going.

Lesson 5: River Travel Then and Now. Have you ever been boating, canoeing, kayaking, or rafting? If so, what did you see? If not, what are some of the things that you think you may see? Students share their experiences, then watch videos and read examples of river explorations through Then and Now stories from historic and modern journeys down the Green and Colorado Rivers to learn about people's experiences traveling down rivers and the science they discover along the way.

Vocabulary: Topographic Map, Population Density, Map Layer, Map Key, Surface Water, Groundwater, Water Cycle, Water Quality, Atmosphere, Sublimation, Precipitation, Evaporation, Condensation, Evapotranspiration, Runoff, Infiltration, Seepage, Tributary, Headwaters


Lesson 1: Where Do People Live Relative to Water?

Engage: In breakout rooms or as a group, ask students to brainstorm all the reasons they can come up with for why water is important to humans. Discuss the wide variety of ways in which water is important to people. Have the students (individually or in small groups) select a location that captures their interests and assist them in finding an appropriate map. Ask the students (or groups) to share why they chose their location and what they noticed about the reservoir/s (ocean, lake, river, stream, glacier) of water in their location.

Explore: To help students discover the relationship between where people live and the presence of water (rivers, lakes, coasts), ask them to make observations about where humans tend to live. If using paper maps, ask students to sketch population density onto the topographic map with colored pencils.

Explain: Have students work in small groups to identify patterns in human population density compared with locations of water. Most groups should notice the relationship between human populations and water reservoirs (ocean, rivers, and lakes). Potential examples include the presence of cities near major world rivers, such as the Amazon, Nile, and Yangtze, the distribution of coastal versus inland cities in Australia, or population density along midwestern rivers, along coastlines and major lakes in the United States. Ask student groups to brainstorm possible reasons why people tend to live near oceans, lakes, and rivers. The goal is to encourage students to discover multiple reasons that humans need water. Answers may include transportation, trade routes, food, fresh water to drink, climate (tends to be milder near oceans). Additional examples of websites related to this topic are included in the blocks at the end of this lesson.  

Elaborate: Have students explore different types of aquatic habitats: wetlands, estuaries, rivers, coastal, oceanic. This could be tailored to the types of habitat/s near the students' location.

Option #1: Students use a familiar note-taking system to research aquatic habitats of interest near them, such as coastal habitats, wetlands, or watersheds. Topics could include: 1) How students, their families, and their communities use this habitat, 2) The types of plants and animals in this habitat, and 3) How indigenous people may have used this habitat.

Option #2: If possible, a short field trip to an onsite or nearby aquatic habitat would be ideal at this point for student interest and relevance. Suggestions for gathering information and staying engaged include:

  • Students record their observations and make sketches in a journal.
  • Students take a set number of photographs, which they can then upload into an online document and annotate back in the classroom.
  • Students run a short experiment or take basic scientific data at the site. If measurement devices are available, students can gather data on water temperature, salinity, clarity, depth, and any other simple measurement (more complex data collection can be done in conjunction with a water quality lesson).
  • Students can identify and/or count aquatic plants.
  • Students can use small vials or jars with lids to collect water, then examine the water samples and sketch their findings. Dissecting microscopes are ideal for this activity. If you do not have access to microscopes, consider borrowing equipment from a local high school.

Evaluate: As a culmination of the activities above, students can prepare a brochure, poster, or presentation to inform their community about their research on the importance of water in their community. This could be done individually or in small groups. If time is limited, a ‘one-pager’ works well for helping students organize their thinking and learning. One-pagers allow students to incorporate visuals, numbers, and words into one space, summarizing the most important points and even tying in literature and/or artwork.


Lesson 2: The Water Cycle

Engage: Students conduct an easy experiment in the classroom or at home to model the water cycle. This can be done as a guided experiment, but one suggestion is to have students explore their own questions and ideas. Alternatively, teachers could create a series of brief activities to explore properties of water that relate to the water cycle, perhaps as multiple stations around a classroom: Consider the options below to engage the students to think about various parts of the water cycle, properties of water, and/or water on other planets.

  • Does water freeze from the top down or from the bottom up? Have students design and conduct a simple experiment using ice cubes in small cups. Why does that matter? What would happen to animals and plants that live in water were to freeze in the opposite direction?
  • Explore and record data on freezing points and boiling points of water.
  • Explore surface tension by counting drops of water that will stay on a penny. Compare results to water that has soap (or another liquid like cooking oil) to demonstrate that surface tension of water is different from other substances. There are numerous resources online to help with this experiment.
  • Students use photos of other planets in our solar system, maps of the world or country, and group discussion to determine why Earth is called the “Water Planet” and discuss why water is important to life on Earth.
  • Students discuss extremophiles (animals that can survive in extreme conditions such as extreme heat, cold, or high pressures - think about deserts or deep ocean environments including hydrothermal vent communities) and discuss their thoughts about whether or not these organisms could survive on other planets or moons.
  • Complete the optional hands-on experiment.

Explore: Use this water cycle diagram to explore the different reservoirs (places where water is held, such as oceans, lakes, rivers, atmosphere, groundwater, etc.) and pathways (movement of water, such as condensation, precipitation, evaporation, infiltration, etc.) of the water cycle. Or, if internet access is unavailable, print copies and walk them through each reservoir and pathway. As an extension, students could take photographs or make sketches to show examples of specific water cycle reservoirs and pathways in their home or neighborhood. This activity can be made culturally relevant by encouraging students to take photographs that show how their family uses water or that document the importance of water in their family or culture. Students can upload the photographs to a shared document and explain or present what they found.

Explain: Using the Water Cycle interactive activity or printed poster: Explain each type of reservoir and pathway. To do this, students can create two sets of index cards: one color of cards to show each reservoir and another color (or an index card cut into the shape of an arrow) to show each pathway. When finished creating the cards, students place each card on a table, on the floor, or on a large piece of paper and agree (or label) which side represents the sky and which side represents the ground, then place each reservoir card where they think each type of water is found (ground or sky) and one pathway card to show how the water travels between each reservoir. Alternately, yarn or string could be used to enhance the visual expression of the pathway cards.

Elaborate: Options for elaboration will depend on the amount of time and depth teachers prefer to spend on this topic and available resources. Suggestions include:

  • Read a picture book aloud that is related to the water cycle.
  • Try the advanced (or intermediate if the class used beginner diagram first) interactive water cycle and have students compare and contrast the two diagrams to learn at a higher level.
  • Participate in a local watershed cleanup day.

Evaluate: Options for end products to consolidate this information could include having students create a water cycle song, poem, rap, dance, or play to interpret the water cycle in their own, creative way.


Lesson 3: Earth’s Water Distribution

Engage: Show students a globe or world map and ask how much of Earth's surface is covered with water (~70%). Next, ask students to guess how much (what %) of Earth's water is fresh water (not salty). Answers will likely range from 0-30%. Then, remind them that the oceans are VERY deep, and thus, most of Earth's water is salty. Explain that you will be exploring freshwater systems next (lakes, rivers, streams, optional: glaciers).

Explore: Have students explore the distribution of salty versus freshwater on Earth by completing this hands-on activity and modifying the materials as needed. Other examples of Earth's water distribution can be found at the USGS Water Science School (and references within) or from the US Bureau of Reclamation. Most importantly, emphasize that less than 1% water on Earth is available for drinking (not salty and not frozen). Show results from the initial survey asking them to estimate the percent of freshwater on Earth’s surface or give them the survey again and show before/after results. Depending on the current mathematical level of your students, the Earth's water distribution could be used to focus on ratios and percentages.

Explain: Read a story about a historical ocean voyage and have the students think about different ways that the people on the journey were able to survive at sea. How did they drink water? Did they bring the water with them? Collect rainwater? Alternately, how do astronauts find water to drink while they are on the International Space Station? See this NASA resource for additional information and ideas.

Elaborate: "Water, water everywhere, but not a drop to drink..." Have students imagine that they are either traveling solo across an entire ocean or are trapped on a deserted island in the middle of an ocean that does not have any rivers, streams or lakes. How would they find any water to drink? Can they think of any way/s to find or collect fresh water to drink? Have them act this out in a play, write a story, or draw a picture of their ideas or inventions.

Evaluate: Revisit the initial question: How much of Earth's water is actually drinkable? Have students create a graphical representation to show this, or as a STEAM (Science, Technology, Engineering, Art, and Mathematics) extension, have them create a sketch, drawing, or painting to show their own creative way to show the amount of salty water versus freshwater on Earth.


Lesson 4: Getting to Know the Colorado River and a River or Stream Near You

Engage: Do students know what types of water bodies are located near their school or home? Do they know where a nearby river starts and where the river flows until it meets an ocean or perhaps the Gulf of Mexico? Show students a map of the United States and point out your local area to ask these questions, then choose at least two different locations across the United States and ask students: Where do you think this river starts? When this river flows downstream, do you think the water will eventually flow into the Pacific Ocean, the Atlantic Ocean, or the Gulf of Mexico? Why? Next, ask the students about the Grand Canyon, and if they know what major river flows through Grand Canyon National Park. Find this river (the Colorado River) on a map and ask students if they know where this river starts, and where it flows after the water travels through the Grand Canyon.

Explore: In this activity, students explore the Green and Colorado Rivers, a major river system in the United States that has sustained life for thousands of generations, has been extensively studied by the USGS for over 100 years, and supplies water for over 40 million people in the West. To do this, use the engaging, interactive USGS map known as Streamer.

1. As a class, navigate to USGS Streamer.

2. Type “Grand Canyon National Park” into the search box in the upper right corner.

3. Ask students where they think this river may start, which direction the river flows, and where the river flows once it leaves the park.

4. Click the “Trace Downstream” tab at the top of the screen, then click the red path of the Colorado River. Discuss what the students observe about the pathway of the Colorado River between Grand Canyon National Park and the Gulf of California.

5. Click the “Trace Upstream” tab at the top of the screen, then click the red path of the Colorado River, which will highlight tributaries over a very large area.

6. Use the zoom slider on the right side of the screen to zoom in on the northern most point highlighted in red and you will find Wagon Creek in Wyoming.

7. Select the “Trace Downstream” tab at the top of the screen, then click the red dot near Wagon Creek.

8. Hover over the red dot near Wagon Creek and you will discover a lot of information about this expansive river system. To summarize, this river system starts at an elevation of 7,801 feet and eventually flows toward the Pacific Ocean (elevation zero). The Green and Colorado Rivers flow for 1,618 miles, are measured by 121 USGS Stream Gages, contain eight named water bodies (lakes/reservoirs), and 7,092,521 people lived near this river system in 2010. Can you imagine what it may be like to travel down this entire river system? What changes in elevation, topography, landscapes, ecosystems, do you think you may see? 

9. Additional questions could explore include:

  • Does the Colorado River meet the Pacific Ocean? Why or why not?
  • Which major cities are within 100 miles of this river system? How far away are Las Vegas, NV and Phoenix, AZ?
  • In 2010, the population of the area near the river was about seven million people, but water from this river supports about 40 million people across the United States. How is this possible? What types of features (pipelines, canals, dams, or other infrastructure) support the distribution of this water?

Research the water levels of Lake Powell and Lake Mead since 2010. How have water levels changed, and why?

Explain: Look at a map of the entire United States to see how your local waterway is connected to all water on Earth.

Elaborate: Next, students explore a nearby river or stream to discover how their local waterway is connected to all water on Earth. Choose a river or stream near your school or home.

  • Hover the cursor over the river.
  • Find the mouth of the river by clicking the Trace Downstream tab, then clicking anywhere along the river.
  • Click the Trace Upstream tab them click the mouth of the river to learn about the connectedness of tributaries and river systems.
  • Record basic data about the river after tracing upstream. For example, the total miles of streams and rivers, number of states, counties, and cities impacted by the river.

Evaluate: Students could investigate their household or community water source to understand how it travels to their home from a reservoir and how the water may be treated before coming out of the faucet. If household water comes from a well or spring, students could ask a parent or responsible adult how to determine how deep the water source is. Students could also explore their local watershed using the USGS Science in Your Watershed interactive map.


Lesson 5: River Travel Then & Now

Engage: Have you ever been in a boat on a river? If so, what did you notice? Was the river small like a creek or large with rapids? What kind of boat (canoe, kayak, or raft) did you use, and why? Did you see large, evergreen trees along the riverbanks, or perhaps small bushes, or even large buildings in a city? Have students discuss their experiences. Alternatively, show photographs of small and large creeks and ask students to observe what they notice and what types of boat they may want to use on each river and why.

  1. Watch and discuss this six-minute video about a historical and modern exploration of the Green and Colorado rivers.
  2. Select one or more readings from the Then and Now series of short essays in this publication (Women in Science: pages 6-7, Art: pages 12-13, Green River, Wyoming: pages 18-19, Food: pages 28-29, Flora and Fauna: pages 38-39, River Travel: pager 58-59, Mapping: pages 68-69, Geologic Time: pages 76-77) which compare several relatable topics from 1869 to 2019. Read one story aloud and discuss or have students read an essay of interest and share what they learned with the class.

Explain: Based on the students' observations of these videos, the readings, and their own life experiences, lead a discussion about the importance of rivers. You could also incorporate what was learned about a local river from the Streamer activity above.

Elaborate: Make one (or more) large rivers in your classroom out of butcher paper rolls. Divide the class into groups and have them write all the things they think they would observe along this river on the river itself. Then, pin it up along one wall of the classroom and refer back to it. A STEAM (Science, Technology, Engineering, Art, and Mathematics) component could be included here as well, such as adding color with markers/crayons/colored pencils, sketches of the animals that may live in the river or the plants that may be along the river, people enjoying the river in specific types of boats, people measuring the flow or water quality of the river.

Evaluate: Compare and contrast historical versus modern river travel. Assign students a culturally-relevant river to investigate, and/or have students draw a picture or write a story about themselves exploring a real or fictional river.



Other Resources

Download free topographic maps

Download free topographic maps

The water cycle diagram

The water cycle diagram

The water in you: water in the human body

The water in you: water in the human body

Earth's salty versus fresh water hands-on activity

Earth's salty versus fresh water hands-on activity

Streamer app

Streamer app

science in your watershed

science in your watershed