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Concept
Earmuffs
Summary
Earmuffs are clothing accessories or personal protective equipment designed to cover a person's ears for hearing protection or warmth. They consist of a thermoplastic or metal head-band that fits over the top or back of the head, and a cushion or cup at each end to cover the ears.
Thermal Earmuffs were invented by Chester Greenwood of Farmington, Maine in 1873, when he was 15. He reportedly conceived the idea while ice skating, and asked his grandmother to sew tufts of fur between loops of wire. His patent was for improved ear protectors, which he and his local employees manufactured in the Farmington area for nearly 60 years.
Thermal earmuffs are worn for protection from the cold. Because the ears extend from the sides of the head to gather sound waves, they have a high skin surface-area-to-volume ratio, and very little muscle tissue, causing them to be one of the first body parts to become uncomfortably cold as temperatures drop. Some people experience this discomfort even if most of the body is comfortably warm, especially during strenuous activity. Wind can often cause the ears to be much colder than the rest of the head. When the ears are uncomfortably cold and the rest of the body is much warmer, using a winter hat or the hood of a jacket to cover the ears may cause the head or body to be uncomfortably hot, possibly inducing perspiration of the head, a dangerous condition in cold weather. Earmuffs can be used to warm the ears only, avoiding overheating other parts of the body or trapping exhaust heat from strenuous movement.
There are two main types of thermal earmuffs. One type has a structure similar to large headphones, with a band going over the top of the head. Another type has two round earpieces made from a material that can produce heat, connected to a thick headband going around and behind the head. Some headbands are thick and wide enough to warm the ears, and are referred to "earmuffs" when used this way.
Acoustic earmuffs are believed to have originated during World War II.
Official source
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