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Learning area: ScienceLevel: Years 7 and 8Water cycle1 Nature of the assessment taskStudents prepare a print or electronic presentation to report to a group of visitors to a sewage plant on their investigation into the cycling of water through ecosystems. They explain their findings in terms of behaviours of water particles and change of state. They identify interruptions to the cycle due to human intervention and describe how this might affect the work of the sewage plant. The completed task is expected to demonstrate the following qualities:
2 Links with State and Territory curriculums
3 Prior teaching and learningFor this task, student should have an understanding of:
(The last two dot-points above, which set a context for the task, could be covered as part of the scaffolding activities.)
4 Teacher preparationThe task has three parts. Parts 1 and 2 prepare students for Part 3, which is the actual Assessment task. Download, read and photocopy the following resource material: Student resources
Teacher resources
Teachers mind find it helpful to examine an annotated worksample for the task. Further information about worksamples and how to use them can be found at this link.
5 Scaffolding: Preparing the students for the taskExplain the nature of the task and how it will be assessed. Make the rubric available to the students. Ensure students understand that Part 1 and Part 2 are lead-up activities for the assessment task, Part 3. SafetyEnsure students know how to handle equipment and carry out procedures responsibly and safely. Part 1: The water cycleIntroduce the task by asking the students to consider where the water they use comes from and where it goes after use. Emphasise that it is a finite resource. Activity One: Students investigate the change of state of water in terms of the behaviour of water particles associated with energy input and energy removal or loss. They refer to the Water facts sheet and record findings on the Change of state diagram. Activity Two: In pairs or small groups, students apply their understandings from Activity 1 to a natural phenomenon – the water cycle – by completing the worksheet, Activity Two: The water cycle. Part 2: Interrupting the cycleIn their groups students discuss likely factors that could interrupt or affect the cycling of water in ecosystems. Likely factors include:
As a whole class activity, you could overlay the diagram of the water cycle on an overhead projector with a transparency. Ask students to indicate where they think interruptions might occur and mark them on the transparency. In their groups, students choose four of the likely factors and explain what the consequences could be to the water cycle. They share their findings with another group, then discuss what actions could be taken to reduce the effect on the water cycle. Because their presentation will be for an audience of visitors to a sewage plant, ask students to identify, in particular, any factors that might be of relevance to the functioning of a sewage plant and to discuss these. Students are expected to make the link between large volumes of water removed from the cycle for urban use, large amounts of run-off and the production of large volumes of liquid wastes and the role of the sewage plant in treating the wastes and run-off. The sewage plant can help water to re-enter the water cycle. Informal opportunities to assess for learning will occur during these activities, and teachers will be able to provide oral feedback to students prior to their beginning the actual assessment task.
6 The taskEach student prepares a presentation suitable for a group of visitors to a sewage plant. They are to provide the science knowledge and understandings necessary for the visitors to understand the water cycle. The presentation may be in the form of a poster with annotations or a printout of an electronic presentation. Students draw on their understandings and evidence from the lead-up activities. Their presentation must include:
Prior to students beginning the task, teachers might consider drawing up a class list of terminology to be used in their brochures. If this list is displayed in the classroom, students will be able to check their spelling and review the content of their brochures. Teachers could also consider allowing students to make a rough draft of their brochure so that they have an opportunity to plan their layout and proofread their written work.
7 Professional adviceThe following diagnostic grid can be used by teachers to record students' performance on each of the expected qualities to obtain a snapshot of those areas in which students will need further instruction. The teaching and learning activities that follow the grid are also related to each of the expected qualities and suggest some ways in which teachers could consolidate or extend student performance. Click here to view how the grid might be completed. Teaching and learning activities linked to the expected qualities listed in the rubrics, and in the diagnostic grid, can be found at the following links:
Teaching and learning activitiesScience concepts and understandingsIf students performed at a low level on this task it might be because they did not make inferences or connections between applying heat energy to change the state of water from ice to liquid, and to vapour and cooling (removing heat energy) to reverse the process. If they had difficulty in explaining the arrangement of particles in water of different states, they could fill a small jar two-thirds full with seeds or beads to represent the arrangement of particles in a solid. What would they have to do to make the seeds move over each other gently? What would they have to do to make the seeds separate from each other? What would they have to do to slow the particles down? (Relate to energy.)
Teaching and learning activitiesApplying understandingsIf students performed at a low level on this task, it might be because they did not understand the processes involved in change of state, were not familiar with the features of the water cycle or were not able to associate the two. This activity could be teacher-directed, or students could work in groups. Overlay an enlarged diagram of the water cycle with a transparency. Point to a particular point in the cycle and ask students to choose the appropriate 'process' word to describe what is happening. Repeat and label the processes that occur in the cycle. Remove the overlay and use another. In a different colour, mark where water could be removed from the cycle. Identify ways that human activity could interrupt the water cycle. Use a mind map to summarise.
Teaching and learning activitiesCommunicating informationIf students performed at a low level on this task, it might be because they found difficulty in using the appropriate vocabulary, or they were unsure of the appropriate techniques to use for the particular form of presentation. To help students build up a useful bank of scientific terminology, encourage them to develop and maintain their own individual dictionaries of scientific terms. On a regular basis, terminology word games could be played. For example teams could draw up lists of questions based on their individual dictionaries (for example: What is ... ? Sedimentary rocks are ones that ... True or False?) and these could be posed, in an against-the-clock situation, to other teams, with points being awarded for correct responses. Teams could also challenge each other's definitions if they believed them to be incorrect. For students who have difficulty processing their information to apply it in another context, consider an interim organisational stage: provide them with a data organiser on which they can write under specified headings, or in answer to specified questions, prior to transferring this information to their brochure or chosen text. Where students were uncertain about the structural features of their chosen form of presentation, provide them with more models of effective examples and provide opportunities for them to discuss the features. Other students' work might be useful material for this purpose.
Teaching and learning activitiesExtension task: TerrariumIf students performed at a high level on the assessment task they could investigate the cycling of water in a simulated ecosystem such as a terrarium. They list the components that they would need to model the water cycle in the closed system, then set up the terrarium in a colourless plastic bottle cut in half or a large screw-top jar. They trace and record the cycling of water over a period of time. Students adjust conditions (variables) to maintain a balance between water inputs and outputs. Ask students to predict what might happen if they were to change variables, for example:
Ask students to give reasons for their predictions. Some useful websites are:US Environmental Protection Agency – Build Your Own Water Cycle
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