Why does a plastic bag make a loud sound when you move it and a cotton bag is almost silent?

Question

Why does a plastic bag make a loud sound when you move it and a cotton bag is almost silent?

In: Physics

Answer 1

Air freely moves through cotton bags, plastic bags are air tight. Since the plastic bag is air tight air that would pass through the bag doesn’t and instead bounces off – this is what sound is, air bouncing around.

Answer 2

The reason plastics bags make noise was already answered: https://www.reddit.com/r/explainlikeimfive/comments/1aqumd/eli5why_do_plastic_bags_make_so_much_noise/?utm_medium=android_app&utm_source=share

So why don’t cotton bags make noise? Cotton fibers are much less rigid than the plastic, so instead of making sound they absorb it.