Plastic Bag Strength
The concept involves filling a plastic shopping bag with heavy items until it tears. Make a hypothesis about what will happen when you “double bag” the same items, lining one bag with another. Conduct the experiment to test your hypothesis. Determine what the relationship is between the number of bags used and the amount of weight that can be held. Repeat the process with three bags; continue until the relationship is discovered. Observe where the bags fail — handles, bottom — and have a consistent, reliable method for measuring the weight that it takes to break each bag or group or bags.
Trash Bag Strength
Compare the tensile strength of trash bags. How much weight can a bag hold before it tears? Does the thickness of the bag make a difference? How does the type of plastic matter? Do bags with fragrance or colors have different elasticity (stretchiness) or strength compared with white or black trash bags?