Question

Why do two layers of cloth of equal thickness provide warmer covering than a single layer of cloth of double the thickness?

Answer 1

Explanation:

Two layers of fabric of equal thickness enclose between them a layer of air which is a poor heat conductor and prevents the body's heat from going out while a single layer of double-thick cloth can not provide enough heat insulation.

Moreover, the fabric and weaving of the cloth also play a role to determine the thickness.