Set up a compost bin and show how recycling household and yard waste translates into better, healthier soil for growing plants. For your presentation, include the complete cycle of life for a common vegetable, such as a cucumber, and how it progresses from seed to produce and then recycles back into the soil to nourish another generation of cucumbers. Be sure to add earthworms into your compost bin and explain their usefulness to decomposition as part of your composting demonstration.
Using a glass pan or an aquarium, create a miniature coastal area using sand, plant seedlings and a solution of salt and water. Add vegetable oil to simulate an oil spill and an ordinary fan to simulate the wind. Show how the oil rides on top of the water and coats the coastline, the underbrush, and everything it comes into contact with. For your backdrop, provide images of the Deepwater Horizon oil spill and cleanup photographs from the Exxon Valdez spill. Document the cost of cleanup as well as the toll spills take on the environment, including such things as the effect a spill has on the entire food chain, up to and including people.
Alternative energy projects might be something as simple as a solar cooker or a solar hot water heater, but a good idea for a more advanced project would be to build a miniature home that is completely powered from alternative sources. Use skylights to minimize lighting needs, provide a solar water heater and solar panel on the roof and a wind-driven ceiling/attic fan combination to keep the home cooler. If you live in an area where such designs are feasible, consider using a partial in-ground home design to reduce heating and cooling costs through the use of soil as an insulator. Be sure to include initial cost estimates and expected returns over the life of the installation.
Demonstrate how coral reefs play an important part in protecting coastlines as well as forming a vital link in the food chain for nearly all marine life. Use well-known coral formations, such as the Great barrier Reef or the Florida Keys, as examples and document the types of organisms found in such habitats. Provide samples of hazards to coral, such as rising waters and changing sea temperatures, and explain how artificial reefs are used in some areas to simulate the effects of living coral. Dedicate all or part of the project to exhibits that portray how protecting the world's coral reefs is beneficial to all living things. More advanced reef projects might investigate medicinal value from coral reefs or document reef conservation projects that are currently being undertaken around the world.