Wool fibres are made of a particular protein (Keratin) which is a bad conductor of heat and as a result does not allow body heat to escape. This helps us in keeping warm during winter. These fibres are wavy in structure, the property commonly known as crimp. Crimp imparts resilience to the fibre due to which fibres quickly recover from wrinkling and crushing. Because of this wavy structure the fibres do not come perfectly close and as a result a large number of air pockets are formed. The air entrapped within these pockets acts as an insulator and traps body heat inside.
