1) The styrofoam holding the peanuts have a lot of air spaces between the groups of polymers as the polymer is made as a foam. Acetone dissolves the Styrofoam, removing the air spaces and thus making the styrofoam much denser.

2a) LDPE cannot be used in this application because it does not have the required strength as compared to HDPE.

2b) The molecules of HDPE must line up in a way that produces the required strength. Thus, using a thin liner of HDPE allows sufficient flexibility.

3) When stretched, the molecules align parallel to each other in the direction of the fool. This change in the structure in not reversible and if it continues, the plastic breaks. The same does not apply to paper since the molecules in paper are held more rigidly thus preventing it from aligning with each other.

4a) Not soluble in body fluids, easy to implant it in the human body, stable over time of use and non toxic.

4b) Contact lens are made from poly(methylmethacrylate) (PMMA). The materials should be permeable to oxygen, comfortable to wear, nontoxic and inexpensive.

4c) Hard contact lenses are usually made of PMMA while soft contact lenses are made of silicone. Soft contact lenses are more comfortable as PMMA is more rigid and does not allow gas to permete while silicone are more flexible and allows for oxygen to reach the eye.