Grade Level: 6th; Type: Chemistry
The goal of this project is to create plastic-like products, predecessors to today’s petroleum-based materials.Additionally, students can initiate the decomposition of the plastic they create by burying the items and recovering them later.This project helps students see the difference between organic plastics and the kinds they are used to.
- How can plastic-like products be made from natural materials?
- How easily do organic plastics decompose?
Before people had petroleum-based plastics, they made semi-permanent items naturally from animal and plant materials.For example, milk mixed with a variety of ingredients was used to seal and weatherproof barns.And, billiard balls made from the byproducts of cotton milling were commonly used until their combustibility was discovered.
The advantage of natural plastics is that they decompose relatively easily.Plastics made from plant and animal products will dissolve in a landfill while many petroleum products never do.
- Half and half
- White vinegar
- Coffee filters—large enough to fit inside a coffee cup
- Coffee cups
- 2 clay flowerpots
- Nonstick saucepan
- Aluminum foil
- Rubber band
- Heat ½ cup of half & half until it begins to foam and remove from the stove.(Use more or repeat for additional supplies of the natural plastic.)
- Stir 1 teaspoon of white vinegar into the half & half until it begins to clump in small curds.
- Layer two coffee filters together and tuck into the cup with the edges wrapped outside the rim and secured with a rubber band.
- Pour the cream mixture into the cup, scraping the pan to get all the curds.
- Wait 5 minutes, remove the rubber band and lift the coffee filters from the cup.Squeeze out excess liquid.
- Unwrap the filters to find a pure white plastic that can be shaped and molded.
- On a piece of aluminum foil, shape the plastic into several small “buttons”.
- Place the plastic buttons on paper towels and allow at least 24 hours to dry.
- After the buttons dry into a hard, yellowish material, put one aside as the control, and gather the others to decompose.
- Fill flowerpots halfway with soil.
- Place homemade buttons in a few pots and real buttons in another.Label the pots.
- Cover the buttons with soil and water them daily.
- After 1 week, uncover the organic buttons from a pot and examine.
- To track the decomposition, continue watering the other pots and recover the organic buttons from those in another week.
- Compare the control, the slightly decomposed buttons and the real ones.
- To visually display this project, record the steps with photographs, and mount the final stages from control to real button on strips of thick cardboard for viewers to lift and examine closely.
Terms/Concepts: Hydrocarbons; Plastic; Polymers
- Plastics and Polymers, Madeline P. Goodstein (2010).