Summer is over and with the exit of the monsoons, winter will soon be upon us. It would be the time to whip out the woollens and stay warm!
Wool, as you may have learnt through rhymes as a child and later on in your science classes, is obtained from sheep, through a process called shearing! Later, it’s processed and made into the garments that we wear.
While we all like cosying up in them, have you ever wondered how woollens – sweaters, mufflers, socks that are made of wool – keep us warm?
Wool is a great insulator (bad conductor) of heat and does not allow your body heat to radiate into the surroundings. Clothes made of wool help regulate your temperature by acting as a natural buffer between your body and the outside of the fabric.
Feeling cold or hot depends on how your body reacts to changes in the external temperature and that in turn, depends on how your body regulates its temperature.
Confused? Here is an explanation.
You may have learnt in your biology lessons about warm-blooded and cold-blooded animals. Warm-blooded animals – like us humans and other mammals – don’t adjust their body temperature based on the weather. In other words, their body temperature remains fairly constant and doesn’t change in tune with the weather outside.
As a result, we warm-blooded creatures need extra insulation to keep our bodies warm during winter. Fortunately for mammals such as bears, wolves and some breeds of dogs, their fur serves as a layer of insulation. For sheep, their coat of wool is their natural sweater and for birds, it’s their feathers.
However, unfortunately, humans only have three layers of skin which are not as efficient against the cold. We resort to wearing heavy clothes so as to not lose our bodies’ warmth.
To better understand how wool does this, let’s dive deep into the reason why we feel cold during winters in the first place and then explore how woollen wear helps us stay warm during winters.
As mentioned earlier, wool is a poor conductor of heat. In other words, it doesn’t let heat pass through.
When you feel cold during the winter, it’s because your body transmits heat to the atmosphere.
Physics says that through the process of conduction, convection or radiation, heat energy is transferred from a hotter to a colder body. During winter, when our bodies are hotter than the temperature outside, and as science dictates, some heat energy from our body radiates into the air around us and we feel cold.
So, how does wool help you stay warm?
Wool as a material has several fine pores. When you wear woollen clothes, those fine pores are filled with air. You may have learnt in science that both wool and air are poor conductors of heat. Thus, together, they don’t let your body heat escape. It’s like a tag team of insulation to keep your body warm and toasty! This also the reason why we sweat when we have too many clothes on.
Here’s how it works: Woollen garments have excellent shape retention because of a feature called ‘crimps’ in the fibres. Crimps are little ridges and folds in the fibres that give wool good insulation properties. It creates many tiny air pockets that trap the warm air of the body and provide insulation from the external air. This insulating barrier protects the body from cold winds.
Some of you may wonder if you can substitute wool with say, cotton. Cotton may not be as effective because they have fewer pores. They hold less air in turn and allow some of our body heat to escape.
You might also prefer to wear woollen over synthetic fabrics too. Synthetic fabrics run the risk of catching fire! However, wool naturally extinguishes itself.
Another property of wool is that it absorbs moisture from your skin while keeping your body free from external chilly winds. As a result, your body stays dry and warm!
Now that you know how wool keeps you warm during winters, can you guess why it’s a good idea to wear cotton during the summers? Share your thoughts in the comments below.
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Aparna is a mom, singer and dreamer. At BYJU'S, she writes stories about learning for children. She believes in the power of music, especially ghazal, the magic of the universe and happy learners. When not writing or singing, you will find her intensely engaged in conversations about life and the power of words.
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