2.1. TOO SALTY FOR ME
(Level: 1 : 2 : 8 :: Water Resources)

Purpose: To illustrate the relative abundance of saltwater and freshwater on the earth.

What You Need:10 litre aquarium :: jar :: water :: 2 glasses :: salt :: tablespoon :: measuring cup :: 2 plants

What You Do:

1. Ask students to name the different places that water exists on the earth and make a list. Emphasize that water on the earth moves around and is found in different places (i.e. underground aquifers), and forms, (i.e. saltwater, freshwater, glaciers, ice caps and snow).
2. Fill a 10-litre aquarium. This water represents all the water on earth. Remove 250ml of water and place it in a jar. This represents all the freshwater in the world, and the aquarium now represents all the saltwater in the world.
3. From the jar of freshwater, 60ml (4 tablespoons), and place it in a glass. This represents all the water that is available for humans, plants, and animals. The remaining freshwater in the jar represents all the freshwater that is stored in icecaps and glaciers and not available for use.
4. Remove 30ml of freshwater from the glass and place it in another glass. This represents all the freshwater that is stored underground. The remaining 30ml represents the water found in the atmosphere, soil, plants, animals, lakes, and rivers.

Questions:

1. With the values given for the amounts of freshwater and saltwater on the earth, construct a pie diagram to illustrate the percentages.
2. How are fish adapted for living in saltwater conditions?
3. How is an amphibian adapted for living out of water?

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Extensions:

1. a) Select two plants that are that as similar to each other as possible (i.e. same species, same size, same type of container, etc.).
   b) Stir some salt into a small glass of water. Explain that this water represents the oceans, and that many plants and animals, as well as humans cannot use water in this form. Use this salt water to water one of the plants and use fresh water for the other (the control).
   c) After two weeks compare the two plants.
2. Discuss water pollution. Because there is relatively little freshwater available, what happens to our freshwater when it becomes polluted? What happens to plants and animals that depend on freshwater for survival? Where do animals that live in water, such as amphibians go when the water becomes polluted?
3. Do a water conservation and water use study in the class. Have students record family water use and aim to reduce overall class use over consecutive months by following one or more water-saving techniques at home. Record water conservation success on a posted chart, calculating the overall volume of water saved. A sample observation sheet can be viewed here (available here if you cannot view pop-up windows).
4. Have students measure the depth of water used in a bath, and compare it to the depth of water used during a shower (put the plug in). Which one uses more water?

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