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Watery Planet    Mystery 1

Water earth mystery 01

In this Mystery, students use estimation and graphing to discover the surprising difference in the amounts of fresh and salt water on Earth.

How much water is in the world?

Beginning Exploration (1 of 10)
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Beginning Exploration (2 of 10)

DISCUSS (1 of 2):

Imagine you were floating alone in a boat on the ocean with nothing. What problems would you face? What would you need to survive?

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Beginning Exploration (3 of 10)

DISCUSS (2 of 2):

I’m sure you thought of many problems you’d face, like needing food to survive. What about needing water to survive? Would that be a problem? Why or why not?

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Beginning Exploration (4 of 10)
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Beginning Exploration (5 of 10)

DISCUSS (1 of 2):

List all the ways that you and your family use water. Imagine what your life would be like if this water disappeared. How would things change?

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Beginning Exploration (6 of 10)

DISCUSS (2 of 2):

How much water do you think your family uses in a day?

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Beginning Exploration (7 of 10)
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Beginning Exploration (8 of 10)

DISCUSS (1 of 2): Make a Guess

Do you think there's the same amount of fresh water and salt water on Earth? Or do you think there's more of one than the other? If so, how much more do you think there is? Twice as much? Five times as much? Or some other amount?

Remember your guess for later.

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Beginning Exploration (9 of 10)

DISCUSS (2 of 2):

Can you think of a way to figure out how much of the earth is covered by salt water and how much by fresh water?

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Beginning Activity Prep
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Activity Prep

Step 1: Plan your time

This is a two-part activity. If you have limited time, you can turn this mystery into two lessons, completing one part of the activity in each lesson.

In the first part, students count squares on maps and record the amount of fresh, frozen, and salt water found in their assigned area of the world. (Steps 1 to 5 on the step-by-step video; questions 1, 2, and 3 on the map worksheet).

In the second part, the results of student calculations are used to make a graph that will reveal how much of each type of water is present on the planet. (Steps 6 to 19 on the step-by-step video; questions 4, 5, and 6 on the map worksheet).

Step 2: Gather supplies

You’ll need:

  • pencils and paper for students to do their calculations
  • markers or colored pencils to help students keep track as they count the squares on their maps
  • scissors and tape to cut out and post classroom materials
  • small, removable sticky-glue dots or Post-its in 3 colors to represent fresh, frozen, and salt water
    • You’ll need at least 80 stickers for salt water and 10 for frozen water, but just 1 for fresh water. You can cut 2” x 2” Post-its into 1/2” strips with a paper cutter or buy 2” x 1/2” Post-its.
  • enough space on a wall or door to accommodate a graph that’s 76 stickers high and 3 bars wide
    • See the photo for the way we did our graph. If you use 1/2” strips for your stickers, as we did, your graph will be 56” high and 30” wide.

sample water graph

Step 3: Print out classroom materials

You’ll need:

  • one copy of the 2-page “Where in the world is my map?” to post for students to see
  • one copy of the Bar Graph Labels (see photo)
  • one copy of the “Map Checklist & Answer Key” for you to use
  • at least one Maps Worksheet (they’re numbered 1–18) for each student…plus extras
    • Each student will need at least 1 of the 18 different maps we’ve provided. If you have a large class, it’s fine for more than one student to have the same map. If you have a small class, distribute at least one map to each student and use the “Map Checklist & Answer Key” to find the rest of the information you’ll need. We’d also suggest printing out an extra of each map used, if possible, in case a student has trouble counting and needs an extra copy.

Step 4: Prepare before class

Before class:

  • Find a good spot for your graph and put the Bar Graph Labels in place
  • Post the “Where in the world is my map?” sheets so students can see the map sections they’ll be working with
  • Have extra maps available, if possible, for students whose first tries don’t work out
  • Have stickers or Post-its for the graph ready to distribute during class

Be aware that counting lots of little squares can be tricky, and counts may vary, even among students working on the same maps. We suggest you remind students that their work should be as accurate as possible, but a few squares off here or there won’t change the graph. Any answer that’s close to the count on the “Map Checklist & Answer Key” will work out fine.

Have fun!

Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Activity: Map the World's Water
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Beginning Exploration (10 of 10)
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Beginning Complete!

You've completed the Exploration & Activity!

If you have more time, view the assessment, reading and extension activity in the optional extras.

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Optional Extras

Below are ideas for extending this topic beyond the activity and exploration you just completed.
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Activity: “Can You Spare a Drop?”

Give students a hands-on feel for how little fresh water is available on Earth with this activity from the University of Michigan.

All you need are:

  • a bucket of water
  • a few measuring cups
  • an eyedropper

This activity includes supporting information and teacher tools. It's fully aligned with the Next Generation Science Standards.

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Readings

These readings are free with registration at Newsela. Articles can be adjusted for reading level. Writing prompts and quiz questions are also available.

  • In this reading, students discover what air bubbles trapped in ice can tell us about the earth’s atmosphere hundreds of thousands of years ago. (Grade 4, also in Spanish)

  • Can toilet water be turned into tap water? Here’s a reading that will REALLY get your students’ thinking about conserving water. (Grade 6)

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Videos on Icebergs and Oceans

  • “What’s Below the Tip of the Iceberg?” (4:51) — Learn how icebergs form and move and create floating islands of fresh water where unexpected life can flourish.
  • “How Big Is the Ocean?” (5:25) How much water is in the ocean? A lot. Hiding under all that water are the world’s longest mountain chain, largest waterfall (yes, it’s underwater), tallest mountain, and deepest canyon.

Click the link below each video for lesson ideas based on the subject. A free subscription to TED Ed gives you access to additional resources, discussion questions, and more. These videos can build your students’ vocabulary. (There are a few advanced words.)

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Discuss — Why do some places use more fresh water than others?

Look at this map from the U.S. Geological Survey. It shows how much fresh water different states in the USA used in 2005. Dark-blue states used more water than light-blue ones.

  • Can you think of some reasons that some states use more water than others?
  • Could climate have anything to do with water use?
  • Do more people live in one place than another?
  • Do people do different types of work in different parts of the country?
  • Can you find your own state? Why do you think it uses the amount of water shown here?
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Image & Video Credits

Mystery Science respects the intellectual property rights of the owners of visual assets. We make every effort to use images and videos under appropriate licenses from the owner or by reaching out to the owner to get explicit permission. If you are the owner of a visual and believe we are using it without permission, please contact us—we will reply promptly and make things right.

Other
groceries by Pixabay , used under Public Domain
planet earth by NASA , used under Public Domain
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