The secret of warmth is air Why is it so light and soft yet warm?

The secret of warmth is air

Why is it so light and soft yet warm?

The charm of cashmere is its warm, fluffy softness and lightness.
Why is cashmere so soft and fluffy and warm?

To keep warm, we need to prevent the cold air outside from taking away the heat from our skin and to keep our own body heat from escaping.
The clothes we wear must of course block heat from the outside air and protect our skin from damage, but they must also be easy to move in, lightweight, and exchange heat appropriately, among other things.
The overall evaluation would be "comfortable to wear.

The major function inside the walls (clothing) is actually "air.
When the air moves (like wind), it causes the skin to volatilize, making it feel cold, but air that does not move has a high thermal insulation effect. This is called low thermal conductivity.
　To feel "warm," the most important issue is how to store a lot of air with low thermal conductivity in clothes.
　Most clothes are made from yarn (of course). The threads are made from various materials such as cotton, hemp, animal hair, and synthetic fibers. Each material has its own characteristics and is used for different purposes, but the raw material of yarn is made by bundling and twisting cotton, hair, and other fibers together.
As you can understand, the finer the raw material of cotton or hair, the more air can be held in the yarn of the same thickness.
Generally speaking, cashmere is the finest animal hair. (I know this is a bit of a long-winded way of saying this, but this is what I wanted to say.)
(This is the point I wanted to make.) You can understand that fine hair is naturally light, soft, and delicate.