Use these free STEM lessons and activities to help students get hands-on building, testing, and exploring the science of the water cycle.
With more than 70% of Earth’s surface covered in water, water is one of the planet’s most abundant natural resources. Thanks to the natural hydrologic cycle (water cycle), water on Earth is continuously recycled. In this process, water shifts between solid, liquid, and gaseous forms, occupying all three states of matter at varying times. As water moves between land, the oceans, and the atmosphere, the distribution of water (where it is located or in what state) is always changing, but the total amount of water on Earth stays approximately the same. Amazingly, the water on Earth today is estimated to be more than a billion years old! (For more information to support introducing the water cycle, see the Teaching About the Water Cycle and the Future notes at the bottom of this resource.)
The free STEM lessons and activities below help students model and explore the water cycle, the various processes, the role landforms and water bodies play, and questions related to sustainability and the importance of water conservation.
The resources below have been grouped as follows:
Note: Science Buddies Lesson Plans contain materials to support educators leading hands-on STEM learning with students. Lesson Plans offer NGSS alignment, contain background materials to boost teacher confidence, even in areas that may be new to them, and include supplemental resources like worksheets, videos, discussion questions, and assessment materials.
Lesson Plans and Activities to Teach About the Water Cycle
In the Make a Miniature Water Cycle Model activity, students make a model of the water cycle in a plastic bag and use it to explore how water moves in and out of the atmosphere in a cycle of precipitation, evaporation, and condensation. The model also enables discussion about how the water cycle includes water that soaks into land, runs off mountains, and gets absorbed by plants. Explanatory information covers infiltration, transpiration, sublimation, and surface runoff. Questions: Why does the water cycle require the Sun? Why is the water cycle important for life on Earth?
In the Make a Water Cycle Model lesson, students learn about the water cycle and investigate how this natural recycling system is powered by energy from the Sun and the force of gravity. Building a physical model of the water cycle in a transparent box and with a lamp as a heat source, students will observe evaporation, condensation, precipitation, infiltration, and surface runoff. Questions: Why is the water cycle a “cycle”? What processes can students identify in the model? How is the water cycle connected to weather patterns?
Evaporation & Condensation
Evaporation and condensation are important processes related to how water shifts between states of matter in the water cycle. Evaporation is the process by which water changes from a liquid to a gas (water vapor). Condensation is the process by which water changes from a gas to a liquid.
3. Make a Cloud
In the Cumulus Maximus: Test WEATHER you can make your own cloud! activity, students explore cloud formation and the processes of vaporization and condensation by making a cloud in a jar. As the temperature in the jar is changed, students will observe how water changes state. As warm air carrying moisture in the form of water vapor rises, it expands and cools. The water vapor then condenses into a liquid form. In a cloud, water droplets attach to dust molecules—it takes billions of these to create a visible cloud. Questions: What role does heat play in cloud formation? Why is water vapor necessary for cloud formation? How are evaporation and condensation related?
Fog is a kind of cloud that touches the ground. Like clouds that form higher in the atmosphere, fog contains moisture that has evaporated into the air and condensed. In the How to Harvest Water from Fog activity, students explore the makeup of fog using a method for harvesting water from the air. Questions: Why is fog more frequent in some areas than others? Ensuring access to a water supply is a global concern. How might harvesting water from fog help?
Precipitation & Melting
Precipitation and melting help move water along in the water cycle. Both represent processes in which the state of water changes to a liquid form. Precipitation is a critical step in the water cycle as it involves liquid or frozen water falling to the Earth. It can be observed in weather events like snow, hail, and rain. The melting of frozen water (ice) also puts water back in motion in the water cycle.
In the Make a Rain Gauge to Study Precipitation lesson, students learn about precipitation and the importance of measuring precipitation for understanding both local and global weather patterns. Using a rain gauge is one way to monitor rainfall. In this lesson, students explore the function and design of a rain gauge and then make their own. Using a hose or homemade “rain maker” watering cans, students can experiment with how a rain gauge works and why rain gauges of varying sizes should record the same amount of rainfall. Question: How are types of precipitation other than rain measured?
The polar ice caps store the second largest amount of water on Earth. (Oceans store the most.) The water in the ice caps is in a frozen state and not in motion as part of the water cycle. However, as temperatures increase with global warming, there is melting at the polar ice caps. What does this melting mean for sea levels? In the How Do Melting Polar Ice Caps Affect Sea Levels? activity, students model the Polar and Arctic ice caps to see what happens to the water they contain if they melt. Question: What is the difference in the formation and location of the ice at the North and South Poles?
Note: The Climate Change and Sea Level Rise lesson provides a related lesson that is NGSS-aligned for grades 5-8. In this lesson, students create and use a model to investigate what will happen to sea levels because of global warming.
Collection & Storage
As precipitation occurs, water is collected and stored in various natural and manmade reservoirs. More water on Earth is in storage than is actively moving through the water cycle at any one time. Approximately 96.5% of the Earth’s water is in the oceans, but water is also stored in other surface-water reservoirs. Natural reservoirs include things like lakes, rivers, ponds, streams, and icebergs. In addition to surface-water reservoirs where water is collected and stored, precipitation is also collected by soil, where it continues to move through the water cycle.
In the Modeling Water Bodies lesson, students investigate different types of water bodies on Earth by using aluminum pans and making models of lakes, oceans, and rivers. Working in groups, students model different types of water bodies. These models enable students to visually observe and compare features of the different types of water reservoirs. Questions: How does water move differently through different types of water bodies? What types of bodies of water store freshwater? How much freshwater is there on Earth compared to saltwater? Why is this a problem for the future?
Note: For a shorter lesson involving the modeling of riverbeds, see the Build a River Model activity.
Does spring water really come from a natural spring? Some water labeled as spring water comes from underground aquifers, layers of rock and sediment underground that are saturated with water. In the How Dirt Cleans Water activity, students explore how surface water and surface run-off seep into the ground where they are stored in underground aquifers. With this hands-on activity, students use plastic bottles to model different reservoirs and investigate to see how clean the groundwater collected from these reservoirs is. Students learn about infiltration and experiment to see how the size of the particles in soil relates to how permeable the soil is and how water moves through the soil. Questions: What happens when water reaches an impermeable layer? What happens when underground areas are saturated with water? What is an aquifer? Why is groundwater often clean (and drinkable) compared to surface water collected in containers like lakes and rivers?
In the Water-wise: Keep Soil Wet Without Waste activity, students investigate how often plants and gardens need to be watered and how much water the ground soaks up. The type of soil, including the size of particles it has and how much organic material it contains, makes a difference in how much water the soil holds. (Keep in mind gravity will also be working to try and pull the water through the soil.) In this science activity, students use everyday foods to model different soil structures and experiment to see how much water each model soil will hold. Questions: What type of soil holds water better, sand, silt, or clay? If soil has larger particles, would it be better to water more or less frequently?
With a finite amount of water on Earth, there are concerns about water availability in the future. In the Exploring Our Growing Need for Water lesson, students explore water sustainability issues, including groundwater depletion, access to clean freshwater, and water waste. Students will also learn about agricultural water use and investigate how the water needed for growing crops compares to the water needed for raising animals on farms and ranches. Questions: What accounts for the depletion of groundwater? Does it take more water to grow crops or raise animals? What kinds of water waste might individual families and communities be able to reduce? See also: Make Environmental Sustainability Actionable for Students with These Lessons.
© 2015 California Academy of Sciences
In the Earth’s Water: A Drop in Your Cup lesson, students explore the distribution of water in various water bodies and reservoirs on Earth and discuss the challenge of stretching the finite amount of water available to accommodate everything that needs it. With almost 97% of the Earth’s water in the oceans and undrinkable without desalination, is there enough water to support life in the future? In this lesson, students do an activity in which 1 liter of water is used to model the planet’s total water. Groups are then given amounts of water to represent different types of water bodies and storage locations, including groundwater, rivers, lakes, ice, and the oceans. Students are then tasked with brainstorming ways to use their allocated water to provide for all of their needs. Questions: What kinds of solutions can you think of to help conserve freshwater? Are there ways to better distribute water? How important is water conservation? Why?
Photo by Tim McCabe, USDA Natural Resources Conservation Service
Teaching about Water Cycle Science in K-12
The water cycle is powered by the Sun and involves processes of melting, sublimation, evaporation, freezing, condensation, deposition, and precipitation as water moves from clouds to land to oceans and back again. While water is abundant, less than 3% of the planet’s water is freshwater (which includes the kind we drink). (Close to 97% of the Earth’s water is in the oceans.) Since water can’t be manufactured by humans, we can’t increase the amount of water on Earth, which means global access to freshwater is a sustainability issue for the future.
The water cycle is also tied to weather systems on Earth. As temperatures rise due to global warming, what changes will occur in the water cycle? Rising temperatures will, for example, speed up evaporation. Similarly, rising temperatures will have an impact on the ice caps. With the relationship between weather, climate, and the water cycle, there are many areas for discussion, research, and exploration with students at all grade levels. As a natural resource in need of conservation, and with many parts of the world facing severe drought scenarios or limited access to freshwater, students, families, and classrooms can also explore sustainability, ecological footprints, and more with lessons in the Earth Day collection. See also: Make Environmental Sustainability Actionable for Students with These Lessons.
The following word bank contains words that may be covered when teaching about weather using the lessons and activities in this resource.
- Dew point
- Global warming
- Hydrologic cycle
- Rain gauge
- States of matter
- Surface runoff
- Surface water
- Water collection
- Water storage
- Water cycle
- Water vapor
Collections like this help educators find themed activities in a specific subject area or discover activities and lessons that meet a curriculum need. We hope these collections make it convenient for teachers to browse related lessons and activities. For other collections, see the Teaching Science Units and Thematic Collections lists. We encourage you to browse the complete STEM Activities for Kids and Lesson Plans areas, too. Filters are available to help you narrow your search.
Development of this resource to support educators teaching K-12 STEM curriculum topics was made possible by generous support from the Donaldson Foundation.