Groundwater activity: build an aquifer in a cup, grades 6–8
What it is: a middle school model where students layer gravel, sand and a clay layer in a clear cup, add water to make an aquifer, and pump from a "well". Then a few drops of food coloring on the surface show how pollution can seep down and reach the well. Students learn that groundwater fills the spaces between rock and sand underground and is a key source of drinking water.
Time: about 40 minutes. Grade: 6–8.
Materials: a tall clear plastic cup per group, aquarium gravel, sand, a flattened layer of modeling clay, a short piece of clear tubing or a straw for the well casing, a plastic pipette or small squeeze pump, water, and red or blue food coloring.
- Ask: "Where does well water come from?" Collect ideas.
- Groups add 3 cm of gravel, then a thin clay layer pressed against the walls, then 3 cm of gravel and 2 cm of sand. Push the tube down to the bottom gravel before adding the top layers.
- Pour water slowly until the gravel below the clay is full. Point out the water filling the spaces: that is the aquifer.
- Use the pipette in the tube to pump water out. Ask: "Where did this water come from?"
- Add three drops of food coloring to the surface sand to stand for spilled chemicals. Pour a little "rain" over it.
- Watch where the color goes over 10 minutes. Pump again. Did it reach the well? Did the clay slow it down?
- Students sketch the model with arrows and write one way to protect groundwater.
Safety: no one drinks the water or puts the straw in their mouth (pump with the pipette only), protect clothes from food coloring, and wash hands afterward.
Differentiation: students who need support build without the clay layer. Students who are ready test a crack in the clay layer and compare how fast the color moves. English learners can use "The pollution moved ___ because ___."
Quick check: ask: "Why can pollution on the surface end up in a well far below?"
For more ideas at this grade, browse the other free activities on the Hub.
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About this resource
- Shared by
- @UpOnlyLearning · Curriculum team
- Posted
- Oct 31, 2026
- Type
- Lesson plan
- Grade
- Grades 6–8
- Subject
- Science
- Language
- English
- License
- Free for classroom, co-op and tutoring use. Please don't resell.