Duration: 30 to 40 minutes
Vocabulary: pollution, model, recycling, impact, point source, non-point source
Summary: Students will create models of their own community/ecosystem and find different sources of pollution and discuss what they could do to stop them.
Objectives: Students will understand where pollution comes from and what it does to our water supplies. They will learn different ways they can work to stop point source and non-point source pollution from occurring, and why this is important. They will also understand the concept of looking to past history to help make decisions about today.
Materials: paint tray, clay, found materials (reusing trash to represent houses, farms, animals, etc), spray bottle, Jello mix of different colors, sponges
Pollution is defined as a contaminant that disturbs an ecosystem. It can either be man-made, or a naturally occurring substance that ends up in a place it does not belong, like large amounts of soil washing into a river because of human disturbance. Pollution can also be in the form of energy, like sound or light. For example, there are very few places left in the United States where you cannot hear any man-made sounds like traffic, or airplanes.
Pollution comes from many different sources. In a community, pollution can come from many sources, including chemicals from factories, car leakage onto roads and parking lots, pesticides and fertilizers used on farms and lawns, manure from farms, chemicals from construction sites, loose soil from construction sites, litter thrown out of cars or from houses, etc. All of these different types of pollution contaminate the habitats they start in (like litter interfering with birds or other small mammals), and also usually end up in nearby streams, wetlands, and even our own water supplies during rainstorms. Once it is in our drinking supply, the resource either becomes unusable or becomes very expensive to ‘fix.’
Many students have trouble with the idea that there is only a certain amount of water on the earth. It can be useful to remind them that the water they are drinking and using now is the same water that the dinosaurs drank! We cannot create MORE water, we can only clean up the water that we currently have. The more our water is polluted, the more expensive and more difficult this becomes.
Explain to students that they will be creating a model of their own community. A model is useful for looking at the different kinds of pollution in their area, because it would be impossible to see all of the sources of pollution and what happens when it rains at once in the real world! Because it is a model, each thing represents part of the bigger picture.
Ask students what pollution means to them, and to think of some sources of pollution they see often in their communities.
Instruct students to make their own watershed model using a paint tray, clay, and other found materials. They can do research ahead of time to learn what kinds of structures are in the community if they are not already sure, like factories, farms, golf courses, construction areas, roads, etc. In small groups they will use the clay to make a town landscape on the upper part of the paint tray, and a stream/wetland/pond area on the lower “downhill” part. They will include roads, and use found materials creatively to represent other structures like farms, golf courses, houses, etc. They will also make something to represent different animals they see in their area (including wetland/stream birds and amphibians) and place them where they think they live.
Once the models are finished have students pinpoint areas that might pollute their community and local habitat. Have them pour Jello powder onto the areas where they think pollution comes from. For example, they might put brown Jello powder onto the construction site, to represent loose soil, or green powder onto the farms, houses, and golf course to represent fertilizer. Small pieces of paper could be scattered around the houses and roadsides to represent litter.
After the ‘pollution’ has been places on the model, have students use a spray bottle or pour water to make it ‘rain.’ The students can watch as all of the Jello powder and bits of paper flow downhill into the water source at the lowest point of the model. The water will turn a brownish color because of all of the different dyes.
Ask students if they would like to drink the water. Ask them if it seems like a healthy place for fish and other animals to live. What is happening to the birds and amphibians now? Explain that now if we want to drink the water, we have to spend lots of money cleaning it to remove the bad things.
Have students gently empty out the water so that the model is clean again and ask them to come up with ideas of how to remove some of the sources of pollution. Some examples would be recycling instead of littering (put less litter on the sides of roads), not using chemical fertilizers, fencing off cows so the manure is not close to water sources (add clay to make a fence), and planting more trees along edges to capture pollution and keep it from getting into our water sources (add strips of sponges around farm, along roadsides, around golf courses, and construction sites). Repeat the exercise with less pollution and new trees and compare how much pollution gets into the water now.
Ask students to name some different sources of pollution that are right in their area. Have them explain why pollution is bad for plants and animals, including humans. Ask them to name three things they could each do personally to reduce pollution.
Have students make additional watershed models to represent an ideal community, or to represent a previous time in their community’s history (either before people built there or before they became more environmentally conscious).
Students could also make new watershed models that include their own ideas for advanced “green” technologies that they hope to see in the future.