Project Grade 4 Art & Music
Lighting the Godwit Point Digester Tanks: A Night Design Project
Grade 4 art teams design night lighting for a fictional plant whose microbes turn sludge into biogas, drawing glowing tanks in chalk pastel and writing a lighting card.
Objectives
- Students will explain that microbes in a sealed digester live without air and break down sludge, giving off biogas.
- Students will build a glow on black paper by working from a bright center out to a soft, blended edge.
- Students will choose a two- or three-color light scheme that stands for a process and follows rules about light direction and warning colors.
- Students will write an informative lighting card that connects their color choices to the science.
Vocabulary
Key words: digester, sludge, microbe, biogas, glow, silhouette, color story, blend
Teacher overview
Many wastewater plants treat the sludge that settles out of used water in digesters, large sealed tanks where microbes that live without air break the sludge down and give off biogas, which the plant can burn for heat or power. The tanks are often the tallest and most visible structures at a plant, and a few cities light their digester tanks at night as public art. This project asks a grade 4 class to act as the lighting designers for the fictional Godwit Point Water Reclamation Plant in the fictional town of Shearwater, whose three round digesters stand beside a riverside walking path and across the street from homes on Sanderling Street. Over four sessions, teams learn what happens inside the tanks, practice drawing light on black paper, design a lighting scheme whose colors tell the story of the process, and present a finished chalk pastel night drawing with a lighting card to a neighborhood council played by the class.
The science misconception to plan for is the belief that every living thing needs air to live. Students have learned that people, animals, and plants depend on air, and many assume the same is true of every living thing. The digester microbes are an exception, because they do their work only in a sealed tank that keeps air out. Ask the class early in Session 1 why the tanks are closed tight, and return to that question when teams choose their colors, since several strong color stories come from the idea of a hidden, airless world inside.
The art misconception is about how light is drawn. Students often show light as yellow lines radiating out from a lamp, the way a cartoon sun is drawn, and they sometimes cover the whole black sheet with dark colors before adding anything bright. On black paper the dark is already there, and a glow is built by placing the brightest color at the light source and blending lighter and then darker tints outward until the color fades into the paper. The practice strip in Session 1 exists to teach this before any final drawing begins, and the rule against pointing light at the sky or into homes gives students a reason to decide exactly where each pool of light falls.
Project Brief
Driving question: How can night lighting help people see the Godwit Point tanks and tell the story of the living things at work inside them?
What happens inside: Shearwater is a fictional town. Used water from its homes and schools flows to the Godwit Point plant. First, the dirty water sits still in big tanks. Heavy solids sink to the bottom. This thick, muddy stuff is called sludge.
The sludge is pumped into three tall, round tanks. They are called digesters. The digesters are closed tight, so no air gets in. Tiny living things called microbes live inside. These microbes do not need air. They eat the sludge. As they eat, they give off a gas called biogas. The microbes work best when they are warm. So the plant burns some of the biogas to keep the tanks warm. After several weeks, there is much less sludge left.
The job: The three tanks stand next to a path by the river. Across the street are the homes on Sanderling Street. At night the tanks look like big dark shapes. The town wants to light them up so they become a landmark. The lights should also tell the story of what happens inside. Your team will design the lighting and draw how it will look at night.
Lighting rules:
- Aim every light at the tanks or down at the ground. No light may shine up into the sky. No light may shine across the street into homes.
- Choose a color story of two or three light colors. Each color must stand for something that happens inside, such as warmth, living microbes, or gas rising.
- Do not use red, and do not make any light flash. People read red and flashing lights as a warning.
- All three tanks must show their round shape, or silhouette, against the night sky.
- Draw in chalk pastel on black paper. Add only the lights and the places where light falls, because the black paper already shows the night.
- Show the river path and the homes across the street. Keep them dim, so viewers can see where the light falls and where it does not.
What you turn in:
- A glow practice strip with three glows.
- Two small lighting plans on black paper.
- One final night drawing on black paper, 12 by 18 inches.
- A lighting card for the Sanderling Street neighborhood council. In four to six sentences, tell what the microbes do inside the tanks. Then tell what each of your light colors stands for. End with a closing sentence.
Milestones
- Session 1 (Inside the tanks and glow practice): Read the story of the Godwit Point tanks with your team. Talk about why the tanks are closed tight. Then practice on a black scrap. Make three glows. For each one, put the brightest color in the center. Add a ring of a slightly darker color around it. Blend the edge with a tissue until it fades into the black. Last, look at the daytime photo and sketch the three round tanks in white pencil on a black scrap. Output: a glow strip with three glows and a pencil sketch of the three tanks.
- Session 2 (Two lighting plans): On the two small black sheets, draw the three tanks in white pencil. Try a different color story on each sheet. Check each plan with a partner: Do any lights point at the sky or at homes? Is there any red? Do all three tanks show their round shape? Put a star on the plan your team likes best. Write one sentence about what its colors stand for. Output: two lighting plans, one starred, with a sentence.
- Session 3 (Final night drawing): Sketch the tanks, the path, and the homes lightly in white pencil on the big black sheet. Add the lights. Build each glow from the bright center out to a soft edge. Let the light fall on the curved sides of the tanks and on the ground below. Keep the homes and the sky dark. Output: one finished night drawing.
- Session 4 (Lighting card and council night): Write your lighting card. Dim the classroom lights and set out all the drawings. Present your drawing and read your card to the council. Council members may ask questions, such as "Will the light shine into my window?" Answer each one using your drawing. Output: your lighting card and your answers to the council.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Rubric
| Criterion | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Color story | The colors are chosen at random, or red is used | The team chose two or three colors, but the reason for at least one color does not connect to what happens inside | Two or three colors each stand for a clear part of the process, such as warmth or gas rising, and no red is used | The color story is clear, and the colors are placed with purpose, such as a warm glow across the body of each tank, where the microbes work, and a cooler color near the domes, where the gas collects |
| Light direction and rules | Light points into the sky or at the homes in more than one place | One light points at the sky or at the homes, or the path and homes are missing | Every light points at the tanks or down, and the path and homes appear dim | All rules are met, and the drawing shows clear pools of light on the ground and a sharp line where the light stops before the street |
| Glow and shape | Light is drawn as lines or flat patches, and the tank shapes are hard to see | Some glows are blended, but edges are harsh or the tanks look flat | Glows move from a bright center to a soft edge, and all three tanks show a round shape against the sky | Glows are smooth and even, and light wraps around the curve of each tank, bright on one side and fading on the other, so the tanks look solid |
| Lighting card | The card is missing or does not explain the microbes | The card names the microbes or the colors but does not connect them | The card explains that microbes eat the sludge without air and give off biogas, tells what each color stands for, and has a closing sentence | The card explains the process in order, connects every color to it, and answers a likely council question, such as why the lights will not bother neighbors |
Differentiation
Support
Give these teams a black sheet with the three tank outlines already drawn in white pencil, so their work in Session 3 goes into the glows and the pools of light. Offer a short list of color stories to choose from, such as "yellow and orange for warmth" or "green for living microbes and pale blue for gas rising." Provide a lighting-card frame: "Inside the tanks, microbes ___. They do not need ___. As they eat, they give off ___. We chose ___ because ___. Our lights will keep the neighborhood dark because ___."
Extension
Ask these teams to design a second lighting scene for a special night, such as the opening of the river path, that changes the color story while still following every rule, and to explain the change in two sentences. A further challenge is to research how the biogas is used at a real wastewater plant, then add a small lit detail to the drawing that shows that use, such as a glowing window on a boiler building.
ELL supports
Teach glow, blend, bright, dim, and sealed with a flashlight, a tissue, and a closed jar before Session 1, saying each word as you demonstrate it. Post a picture strip of the process (dirty water, sludge, sealed tank, microbes, gas) with one word under each picture. Allow the lighting card to use the sentence frame with short phrases, and let students practice their council answers with a partner before presenting.
Extensions
Search with the class for photographs of digester tanks lit at night, and compare how those lighting designers used color and where they aimed the light. If the local water utility gives tours, ask whether its plant has digesters and how it uses the biogas, and add what students learn to their lighting cards. Students who enjoyed the glow technique can use it again for a drawing of a water tower or a bridge at night, keeping the same rule that light points down and away from homes.