7th Grade Water Cycle Essay


Updated Diagram:

This updated water cycle diagram from the USGS is perfect for kids! It does a great job of explaining how the water cycle works using simple language and colorful illustrations that kids will enjoy. Check out the giant 1550 x 1105 version and see for yourself! (opens in a new window)



Heat from the Sun causes water on Earth (in oceans, lakes etc) to evaporate (turn from liquid into gas) and rise into the sky. This water vapor collects in the sky in the form of clouds.


As water vapor in the clouds cools down it becomes water again, this process is called condensation.


Water falls from the sky in the form of rain, snow, hail, or sleet, this process is called precipitation.


Oceans and lakes collect water that has fallen. Water evaporates into the sky again and the cycle continues.




In a process similar to sweating, plants lose water which is absorbed into the atmosphere much like evaporation. The combination of evaporation and transpiration is known as evapotranspiration.


It is possible for a solid to transform into a gas directly (without becoming a liquid). The most common example of sublimation is dry ice (solid carbon dioxide) which sublimes at normal air temperature. Under certain conditions snow and ice can also sublime.

Water: A Never-Ending Story

A curriculum module intended for grades 4-5.

Approximate time frame: 2 weeks.

I. Teacher Background

    Water on earth is used over and over. The water cycle, the continuous movement of water from ocean to air and land then back to the ocean in a cyclic pattern, is a central concept in meteorology. In the water cycle, the sun heats the Earth's surface water, causing that surface water to evaporate (gas). This water vapor then rises into the earth's atmosphere where it cools and condenses into liquid droplets. These droplets combine and grow until they become too heavy and fall to the earth as precipitation (liquid if rain, solid if snow).

    Water is temporarily stored in lakes, glaciers, underground, or living organisms. The water can move from these places by streams and rivers, returns to the oceans, is used by plants or animals or is evaporated directly back into the atmosphere.

II. Module Goals-- students will:

    1. Understand that water on earth moves in a continuous cycle.
    2. Be able to name and explain the stages of the water cycle.
    3. Be able to use Internet data to access information about the water cycle on the Olympic Peninsula of Washington State.

III. Overview of the Module

    In this module, students will first carry out a number of activities that demonstrate the concepts of evaporation, condensation, precipitation, and soil moisture and runoff. The students will then construct a terrarium as a way to observe the water cycle as a whole. Immediately following this, students will use the Internet to acquire Real Time Data from the Olympic Peninsula which they can then use to describe how the phases of the water cycle look on the Olympic Peninsula.

IV. Introducing the Module

    To begin the module teach your students the "WATER CYCLE BOOGIE." This is a song that teaches the terminology of the water cycle with hand movements.

    After teaching the song, have a class discussion to explore students prior knowledge of the water cycle. Use the following questions to determine what concepts the students understand and to identify misconceptions.

    The objective of these introductory activities is to build interest in the water cycle. This activity will allow the students to use their prior knowledge about the water cycle and to spark their interest so that they want to learn more.

    Discussion questions

      1. Does the earth have more or less water now than 1,000 years ago? Explain.
      2. From where does water that is on the ground come?
      3. How does water get into the oceans?
      4. What are clouds?
      5. What are clouds made of?
      6. How does rain form?
      7. What do you think all those words we used when we sang the "Water Cycle Boogie" mean?

    After discussing these questions with your students, explain to them that they are going to carry our several activities that will help them to better understand the water cycle.

V. Activity Set Up

    These activities should be conducted in cooperative groups of 2-3 students. This will allow the students to have personal involvement in the activities and help them construct their own understanding of what is happening. This will require materials and set-up for each group. If small group works are not possible the activities might also be set up as centers. Groups of students could then rotate through each station. This approach would require fewer materials and less set up. A final option would be to conduct the activities as a teacher directed demonstration with the whole class observing. This would require fewer materials and less set up, however, it is recommended only if the two options discussed above are not possible.

VI. Teacher Preparation of Activities

    Students will begin the activities after the introduction to the lesson which asks them to think about if the water they drink is the same water dinosaurs drank. Each activity should begin with some opening questions, which should be discussed with the whole class, and conclude with a set of questions that students will answer in writing.


    1. Materials (for groups of 2-3 students)

      small dishes or jar lids (2 per group)
      tablespoons (1 per group)
      light source (sun or lamp/light) (1 per group)
      plastic wrap and or lids to cover dishes

    2. Discussion questions

      a. Prior to the activity
      Where does the water go after it forms puddles on the pavement?
      Where does the water go from the clothes you put in the dryer?
      Ask students to predict what will happen to the water if it is left out overnight in an uncovered dish.
      Ask students what will happen if the dishes were covered.

      b. After the activity
      Have students, on a sheet of paper answer these questions with a partner.
      Which dish evaporated faster?
      Where did the water go?
      How did the water evaporate?

      c. Explain to the students that the process of water "going" into the air is called evaporation. Have students discuss with their partner what happens to water after it evaporates. Write some other examples of evaporation.

    3. Procedures

      Divide the class into pairs. Have each pair of students get two dishes. Put one tablespoon of water in each dish. Place one dish in the sunlight, or if the sun isn't shining, place the dish under a light source. Let students decide if they want to cover their dishes or leave them uncovered. Place the other dish in the shade. Have each pair of students observe and record what happens to the water.


    1. Materials (for groups of 2-3 students)

      A clean, clear 2 liter plastic bottle for every 3 students
      A box of wood matches for every 3 students
      A thermometer for every bottle (available at fish stores)
      An eye dropper or other container for water

    2. Discussion questions

      a. Prior to the activities
      What makes air warm? What happens to warm air?
      What makes air cold? What happens to cold air?
      What are clouds? How are clouds made?
      What 3 things are necessary to form clouds?
      What is fog?

    b. After the activities

      Have students answer this question in writing: In your own words explain what we did in these two activities. What do you know about the relationship between air temperature, air pressure, condensation, and the formation of clouds?

    3. Procedures

      It is recommended that these activities be carried out over two class sessions. The first session is part 1 and second session is part 2.

      Session 1: Temperature changes in a closed pop bottle
      Tell students that they will work in groups of 3.
      Each group will have:
      1 clear plastic bottle with cap
      1 temperature strip
      1 strip of tape
      1 Box of Matches
      1 paper on which to record their data
      The first step :
      Tape the temperature strip into the bottle so that you can read it. Then screw the bottle cap on tightly. Lay the bottle on its side so you can easily read the temperature strip.
      Read and record the temperature of the air inside the bottle. Then use both hands to squeeze the bottle as hard as you can. After about 1 minute read the strip. Then stop squeezing and read the temperature strip after about 1 minute.
      What happened the temperature when you squeezed the bottle.
      What happened to the temperature when you stopped squeezing the bottle?

      Session 2: Making a cloud-in-a-bottle
      Open the bottle and pour in a few drops of water. Screw the bottle cap on tightly. Swirl the water around the inside of the bottle so that most of the inside of the bottle is wet. Squeeze the bottle and observe the temperature again. What happened?
      Lay the bottle on it's side, open the bottle, and push down to flatten the bottle to about 1/2 it's normal size. Have someone light a match, blow it out, and put the match into the bottle while it is still smoldering. Quickly release the sides of the bottle and put the cap on tightly. Now squeeze the bottle as before very tightly for about 1 minute. Quickly let it pop open.
      What happens? Hopefully, you should be able to see a cloud. In this experiment you saw water molecules condense into a cloud in the bottle. When you squeezed the bottle the air pressure in the bottle increased which raised the temperature. The warmer air caused the water in the bottle to evaporate (it became water vapor) and you could not see it. When you let the bottle pop out the air pressure in the bottle was lowered and so was the temperature. This caused the water molecules to condense into a cloud

    C. Precipitation Activity

      1. Materials

        A heat source to boil water
        A pot in which to boil water
        A Pyrex or other container with a handle
        Ice cubes
        A pie pan or other container

      2. Discussion questions

        a. Prior to the activity
        What is rain? How does rain happen? What is snow? How does snow happen? What is hail? Ask students immediately before activity What do you think will happen to the bowl of ice, to the steam, to the bottom of the bowl?
        Tell the students they need to focus on these questions during the activity. What do you see happening on the bottom of the bowl? What do you see happening in the pie tin? How does the water get on the bowl? Are the water drops on the side of the bowl the same size? Why? Which drops are falling from the bowl? Why? Which drops look like rain? Which drops look like a cloud? How are the big drops formed?
        b. After the activity On a sheet of paper answer these questions with a partner. What did you see happening on the bottom of the bowl? What do you see happening in the pie tin? How did the water get on the bowl? Were the water drops on the side of the bowl the same size? Why? Which drops were falling from the bowl? Why? Which drops looked like rain? Which drops looked like a cloud? How were the big drops formed?
        Explain that the small misty drops which have condensed onto the side of the bowl of ice represent a cloud. The winds in a cloud blow the small drops around so that they collide with one another. During these collisions, some drops will combine with others making bigger and bigger drops. When the drops become so large that the upward motion of the air cannot keep them in the sky, the drops fall as precipitation. If the temperature is cold enough the drops will freeze as crystals, making snow. If the drops get together first and then freeze the precipitation will be hail.

      3. Procedures Set up this activity where students can gather around you and see what happens to the pot with ice in it and to the moisture that drips from the pot into the pie tin. Place a pot of water on the heat source until it comes to a boil. Fill the Pyrex pot with ice. Once the water is boiling, hold the bowl of ice over the steam. Place the pie tin so that the water which drips from the bottom of the bowl will collect in the tin. Continue to hold the pot of ice over the boiling water until all the students have had a clear view of what is happening on the surface of the pot with the ice.


      1. Paper and a writing tool
      2. Discussion questions What kinds of precipitation are there? What happens to precipitation when it reaches the ground? How can water be stored?
      3. Activity Make a list of all the places that water goes once it reaches the ground. Divide students into groups and have them make sketches or drawings as well as written descriptions of what happens to the water when it lands in these places. Have a class sharing and discussion about the answers generated.


    1. Materials for every 2 students

      About 100 ml (half cup) of each of a variety of soils
      A funnel
      Filter paper disks folded into cones, one for each soil type
      A graduated cylinder (or a teaspoon)
      A jar of water
      A tray or other container which will catch water

    2. Discussion questions

      a. Prior to the activity
      From where does ground water come?
      What causes streams and rivers?
      Do different types of soil hold different quantities of water?
      Explain that the funnel is used to 'channel' the water once the soil has absorbed all it can hold.
      b. After the activity
      On a sheet of paper answer these questions with a partner. How did you know the soil was saturated?
      What happened to the water once the soil was saturated?
      Where does water go after it runs to a stream? (List at least 2 possibilities.)

    3. Procedures

      Every 2 students will put a cone of filter paper in a funnel. Place 100 ml (about 1/2 cup) of dry soil in the funnel and tamp the soil gently. Pour 5 ml (about one teaspoon) of water onto the soil every 30 seconds until water appears at the bottom of the funnel. Repeat the experiment with the other soils and a new filter cone. Have students describe what process happens between the water and land to form streams.


    1. Materials for terrarium activity

      Potting soil
      A package of seeds e.g. marigold or pea
      Container for pouring water.
      A plastic container e.g. small like you can get at the grocery for salad.
      (Check with your local water department they may have the materials for a terrarium they will give you.)

    2. Discussion questions

      a. Prior to building the terrarium
      How do all of the parts of the water cycle fit together?
      What would happen if one part was left out?
      b. After building the terrarium
      Observe what happens to the water in this closed container and help the students observe and describe the different parts of the water cycle they see in the terrarium.
      Keep track of your observations in a science journal. Each day look for the following things:
      What is the seed doing?
      On which parts of the terrarium do you see water?
      What new is happening in your terrarium today?

    3. Procedures

      Review the water cycle boogie and then have the students do it. Explain that each student will get to build or have their own terrarium to observe the water cycle. Provide each student with a small plastic container which can be covered tightly with either a clear lid or plastic wrap. Have each student put soil in the bottom, put a plant seed in the soil, and lightly water the soil. Cover the terrarium with the lid or plastic wrap and place in a location where it can get sunshine


    After conducting the activities which introduce them to the phases of the water cycle, students will now apply what they have learned by looking at data from the Olympic Peninsula to see how the water cycle occurs there.

    1 Students will be directed to view a National Weather Service precipitation map (http://www.ocs.orst.edu/pub/maps/Precipitation/Total/States/WA/wa.gif) for Washington state. Questions.

    • Which areas get the greatest amount of rain? How much?
    • Which areas get the least amount of rain? How much?
    • Why is there such a difference?

    2 Students will then be directed to a precipitation map of a relatively dry area of the Olympic Peninsula. The area is near a town called Sequim, which is pronounced "skwim." (http://www.sequim.com/maps/rainfall.html) Students will investigate present and monthly rainfall and calculate the likelihood of rain using archived data (http://www.sequim.com/cgi-bin/weatherstation).

    3 Students will collect information on Forks, a town on the West coast of the Olympic Peninsula (http://www.atmos.washington.edu/cgi-bin/forecast_obs). They will be asked if they think it is raining in the Forks area right now. Students will compare the differences in precipitation between Forks and Sequim.

    4 Students will then be directed to study a relief map showing the topography of the Olympic Peninsula (http://www.olympus.net/travel/peninsula.html).

    1 Study the relationship between the rainfall at Forks, stream flow data, and the level of Lake Quinalt. Students will be directed to go to the Web site for the Olympic Rain Forest (http://www.wrldpwr.com/quinalt/quinalt.html) to get information on Lake Quinalt and stream flow information for the Olympic Peninsula.

    2 Students can be assigned to collect and record data from the Internet sites and make assumptions about what the data means in terms of the particular part of the water cycle.

VII. Assessment

    Assessment will be carried out throughout the lesson in the form of discussions and the written responses to the various activities. The final assessment will be to have each student answer the following question: WHERE DOES WATER COME FROM AND WHERE DOES IT GO? Students should be allowed to answer this question in a final project that would be chosen from the following:

    Draw or paint the answer to the question. Write a poem to answer the question. Write a life history of a raindrop. Present a play that answers the question. Use Super Paint or Kid Pix to graphically answer the question.

VIII. List of Various Science Standards met by this module

    AAAS Benchmarks for Science Literacy

      K-2 "Some events in nature have a repeating pattern." "Water left in an open container disappears, but water in a closed container does not disappear."
      3-5 "When liquid water disappears, it turns into a gas(vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets of water."
      6-8 "The cycling of water in and out of the atmosphere plays an important role in determining climatic patterns. Water evaporates from the surface of the earth, rises and cools, condenses into rain or snow, and falls again to the surface. The water falling on land collects in rivers and lakes, soil and porous layers of rock and much of it flows back into the ocean.

    AAAS Science for all Americans

      "The cycling of water in and out of the atmosphere plays an important role in determining climatic patterns--evaporating from the surface, rising and cooling, condensing into clouds and then into rain or snow, and falling again to the surface, where it collects in rivers and lakes, and porous layers of rock. There are also large areas of the earth's surface covered by thick ice (such as Antarctica), which interacts with the atmosphere and oceans in affecting worldwide variations in climate."

Washington State Essential Academic Learning Requirements (EALRs)

    pg. 14. Use properties and characteristics to identify, describe, and categorize substances, materials, and objects.
    Benchmark 1.(b) Use physical properties to describe the three state of matter. pg. 15 "measure properties and characteristics."
    Benchmark 1 identify and correct sources of error in measurement.
    Benchmark 2 identify and manage sources of error in measurement.
    pg. 18 "Understand that interactions within and among systems cause changes in matter and energy."
    Benchmark 1 Describe the changes of state of common substances like water.
    pg. 19 "Understand that interactions within and among systems cause changes in matter and energy."
    Benchmark 1 Know water is cycled from ocean to air to land, and back to ocean.
    Benchmark 2 Explain how energy from the sun drives the water cycle.
    pg. 21 "Conduct scientific investigations."
    Benchmark 1 Make simple, accurate observations. Use tools, technologies, and information to conduct simple scientific investigation. Plan and conduct a simple experiment.

NRC National Science Education Standards

    Teaching Standards:
         A (pg. 30), B (pg. 32), C (pg. 37), D ((pg. 43), E (pg. 45)
    Professional Development Teachers
         C (pg. 68)
    Assessment Standard
         A (pg. 78), B (pg. 79), D (pg. 85), E (pg. 86)
    Science Content K-4
         A (pg. 121), D (pg. 130), G (pg. 141)
    Science Content 5-8
         A (pg. 143), B (pg. 149), D (pg. 158)
    Assessment Standard
         A (pg. 78), B (pg. 79)


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