Lesson plan Grade 8 Art & Music
Designing a Reverse-Osmosis Exhibit Panel and Its Label
A grade 8 art lesson where students design a museum exhibit panel that shows how a reverse-osmosis membrane cleans water, then write its explanatory label.
Objectives
- Students will design an exhibit panel that shows the steps of reverse osmosis in a clear left-to-right order.
- Students will write a short explanatory label that names the parts of the process using precise vocabulary.
- Students will use arrows, labels, and grouping so a visitor can follow the diagram without help.
Vocabulary
- Reverse osmosis
- Reverse osmosis cleans water by pushing it through a membrane with holes so tiny that salt and most other dissolved things cannot fit through. It can even turn seawater into fresh water.
Also: membrane, semipermeable, concentrate, exhibit label
Teacher overview
A good science museum panel does two jobs at once: a diagram shows how something works, and a short label puts that process into words a visitor can follow while standing up. In this lesson students design an exhibit panel about reverse osmosis, the membrane process that pushes water through an extremely fine filter to leave salt and other contaminants behind. The panel is for a fictional science center, the Rivermouth Water Discovery Center. Students plan the diagram so it reads in order, then write the explanatory label that walks a visitor through each step. The design challenge is making an invisible, molecule-scale process readable at a glance.
Procedure
Hook (5 min): Ask students how you could show, on a wall, something too small to see: water molecules squeezing through a filter with holes far tinier than a grain of salt. Collect a few ideas about arrows, labels, and cutaway views, and tell students that is exactly the design problem a museum faces.
Direct instruction (12 min): Explain reverse osmosis in plain terms. Ordinary filters catch large bits; a reverse-osmosis membrane is semipermeable, meaning it lets water molecules pass but blocks dissolved salts and many other contaminants. A pump pushes the source water against the membrane at high pressure. Clean water, called the permeate, passes through. The leftover water carrying the concentrated salts, called the concentrate, is carried away. Draw the three-part flow on the board left to right: source water in, membrane in the middle, two streams out. Introduce the design tools that make a diagram readable: a consistent left-to-right or top-to-bottom flow, arrows that show direction, labels placed close to what they name, and grouping so related parts sit together.
Analyze a sample panel (8 min): Show a printed cross-section reference of a membrane and one sample exhibit layout. As a class, trace the path a visitor's eye takes and check whether the arrows and labels make the order clear. Identify one thing that works and one thing that could confuse a visitor.
Sketch the panel layout (10 min): On poster board, students lightly sketch their panel: where the source water enters, where the membrane sits, and where the permeate and concentrate exit. They place arrows and leave space for labels. Detail and color come only after the flow is correct.
Write the explanatory label (10 min): Students write a short label of three to five sentences that names each part and explains, in order, how reverse osmosis cleans the water. They are told to use the precise words membrane, semipermeable, permeate, and concentrate at least once each, and to keep sentences short enough for a standing visitor to read.
Closure and formative check (5 min): Partners trade panels and read only the diagram, without the label, then guess the order of the steps. If a partner cannot reconstruct the order from the diagram alone, the designer marks one arrow or label to fix. As an exit ticket, each student writes the one sentence of their label they think a visitor would remember.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
Model exhibit label (teacher reference): "Reverse osmosis cleans water by forcing it through a semipermeable membrane, a filter so fine that water molecules pass but dissolved salt does not. A pump pushes the source water against the membrane at high pressure. The clean water that passes through is called the permeate, and it flows to storage. The leftover water, now carrying concentrated salt, is called the concentrate, and it is carried away for disposal or further handling." Accept any label that names the membrane, states that a pump provides pressure, and correctly separates the permeate (clean) stream from the concentrate (salty) stream in the right order.
Diagram check: A complete diagram shows source water entering one side, the membrane in the middle, and two labeled streams leaving: permeate (clean) and concentrate (salty). Arrows should show the source water moving toward the membrane and the two streams moving away from it.
Differentiation
Support
Give students a partly drawn panel with the three zones (source water, membrane, two exit streams) already outlined, so they can concentrate on placing arrows, labels, and the written explanation. Provide a sentence frame for the label: "Reverse osmosis works by ___. First, ___. Then, ___."
Extension
Ask students to add a small second inset to their panel showing what would happen without the membrane, and to add one sentence to the label explaining why the membrane, not just the pump, is the part that actually cleans the water.
ELL supports
Provide a labeled vocabulary card with a simple icon for membrane, permeate, and concentrate. Allow the exhibit label to be drafted first as a labeled sketch, then turned into sentences with a partner, and accept the exit ticket as a spoken sentence.
Extensions
Compare the class panels with a real museum or utility explainer on how desalination or membrane treatment works. Students note which design choices professionals used, such as color coding the clean and salty streams, and revise one element of their own panel to match a technique they found effective.