There are three different kinds of polymers used for kitchen plastic wrap: low density polyethylene (LDPE) (e.g., Handiwrap or Glad Wrap), polyvinyl chloride (PVC) (e.g., Reynolds PVC Foodservice Wrap or Boardwalk PVC Food Wrap Film) and polyvinylidene chloride (PVdC) (e.g., Saran Wrap, which is almost 90% polyvinylidene chloride). Which of these materials is least permeable to oxygen? When you slice an apple, the surface of the slice turns brown as the apple is oxidized. Can plastic wrap seal out oxygen and prevent the apple from browning? Which plastic wrap works best? Do background research on the different polymer types used for plastic wraps in order to develop a hypothesis. Use samples of each type of plastic wrap to cover three slices for each wrap. Cut the wraps with a pair of scissors so you do not stretch the material. Prepare your wraps in advance so that you can wrap each slice right after it is cut, since oxidation starts immediately. Be sure to keep three slices unwrapped as controls for comparison. Compare the slices at regular intervals and note your results. For more ideas on how to do the actual experiment, see the Science Buddies' science project idea Yuck, What Happened to My Apple? How Food Wrappings Affect Spoilage. Also, you may want to take pictures to use for your Science Fair Project Display Board. Do you think you would get the same results at a different temperature? How about if the slices were on saucers covered with plastic wrap? Does stretching the plastic make any difference? Can you think of other ways you might test oxygen permeability of plastic wraps? (Goodstein, 2004, 65-69)
There are three different kinds of polymers used for kitchen plastic wrap: low density polyethylene (LDPE) (e.g., Handiwrap or Glad Wrap), polyvinyl chloride (PVC) (e.g., Reynolds PVC Foodservice Wrap or Boardwalk PVC Food Wrap Film) and polyvinylidene chloride (PVdC) (e.g., Saran Wrap, which is almost 90% polyvinylidene chloride). Which of these materials is least permeable to oxygen? When you slice an apple, the surface of the slice turns brown as the apple is oxidized. Can plastic wrap seal out oxygen and prevent the apple from browning? Which plastic wrap works best? Do background research on the different polymer types used for plastic wraps in order to develop a hypothesis. Use samples of each type of plastic wrap to cover three slices for each wrap. Cut the wraps with a pair of scissors so you do not stretch the material. Prepare your wraps in advance so that you can wrap each slice right after it is cut, since oxidation starts immediately. Be sure to keep three slices unwrapped as controls for comparison. Compare the slices at regular intervals and note your results. For more ideas on how to do the actual experiment, see the Science Buddies' science project idea Yuck, What Happened to My Apple? How Food Wrappings Affect Spoilage. Also, you may want to take pictures to use for your Science Fair Project Display Board. Do you think you would get the same results at a different temperature? How about if the slices were on saucers covered with plastic wrap? Does stretching the plastic make any difference? Can you think of other ways you might test oxygen permeability of plastic wraps? (Goodstein, 2004, 65-69)
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