It's (zipped) in the bag

Plastic baggies, especially the sealable variety, seem to be a ubiquitous part of human culture. The zipper-type seal on plastic baggies is an example of an unappreciated engineering accomplishment that is relevant to everyday life. In fact, the challenge of fastening two pieces together probably dates back to the making of tools and clothing by early humans. The seal on a plastic baggie illustrates the creativity engineers used to find a very simple, yet elegant, solution to a problem. This article explores the origins of the sealable plastic bag and discusses a lesson in which students investigate different types of sealing mechanisms on plastic bags and then design their own sealing mechanism. (Contains 1 resource and 5 figures.)