In this lesson students learn that water is an important resource that occurs naturally in solutions and is cycled through the environment by naturally occurring separation techniques.
Distribute the worksheet Separating mixtures review (Word, 387 KB) and ask students to complete. Discuss student responses.
- Ask the students which separation technique enabled them to obtain fresh water, and if they are familiar with this, how large quantities of fresh water are provided for human consumption. (Some students may know about desalination plants.)
- Tell students that fresh water is an important resource that all living things need for their survival but only 5% of all water on Earth is fresh water and only 15% of this (0.75% of all water) is drinkable. Explain that Australia is one of the driest continents on Earth and discuss with students why is it important to conserve water and to prevent contamination of our water supplies.
- Ask students how fresh water supplies are replenished naturally. Show the students the image of the water cycle and identify water as a renewable resource.
The water cycle.
- Distribute the worksheet Understanding the water cycle (Word, 751 KB). Ask students to complete the diagram and questions.
- Examine the water cycle, explaining the main processes and how they contribute to renewing fresh water supplies. Have students work through the learning object Making water drinkable: water and us.
- Conduct the activity See for yourself how filtration works (Word, 551 KB).
Discuss the consequences of pollutants getting into aquifers and whether or not filtration would remove these.p>