In this lesson, students understand what polymers are and the role that they play in their everyday life. After gaining the initial understanding of polymers, students create and test a polymer (silly putty) to reinforce understanding of polymers. Students then make connection on microscopic level structure to macro level properties such as highest bounce or longest stretch by changing the ratios of material to get silly putty with desired attributes through engineering design. This lesson helps students understand that desired properties in a designed material are a result of manipulation of structure at the molecular- level. A particular strength of this lesson is connection with the engineering design.