system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does plastics make so much noise when you wrap it even though it is so soft?
gpt
Plastic wrappers make noise when crumpled because of those creases and ridges you see on it. Unlike very elastic materials like rubber sheets, when you stretch a plastic sheet, the stress doesn't get distributed evenly. Treated plastics have metastable energy minima.

When you apply more force after the first crumple, these facets release some elastic potential energy they were storing, (Ridges store 4/5 of the total energy in your plastic wrapper), they buckle and form a new facet with a new orientation. The energy is released in the form of sound clicks, heat and vibrations.