Elastic Plastic

This week we investigated polymers. Plastic bags are polymers. They are strong, stretchy and like elastic. We filled the plastic bag half full of water and we poked meat skewers through the bag, through the water and out the other side. We thought that the bags would leak but surprisingly they didn’t. When the skewers were removed the bag was like a watering can. Water squirted out of the bag. We wondered if the bags would hold air in the same way that they held water when they were pierced with the meat skewer. We tried it. Today, two days later the bag it is still finflated with the skewer still in place. We decided the skewer was a bit like a plug fitting tightly enough to stop water or air escaping. We thought the stretchiness of the bag closed tightly around the bags.