Earmuffs Day

What the day is

Earmuffs Day is observed on March 13, marking the 1877 patent granted to Chester Greenwood of Farmington, Maine.

Origin and background

The story is unusually well attested for this kind of invention. Greenwood was a teenager who found that his ears hurt too much to stay out skating through a Maine winter, and that wool wrapped around his head made him itch. He bent wire into loops, had his grandmother sew fur and cloth pads onto them, and patented an improved hinge design at fifteen. He then manufactured them in Farmington for decades, and the town supplied earmuffs in quantity through the First World War.

The physics is straightforward and worth knowing. The outer ear is thin, highly vascular and almost entirely exposed, with very little insulating fat, so it loses heat quickly and is among the first places to develop frostbite. Earmuffs work by trapping a layer of still air against the skin, which is the same principle as any other insulation: the material matters far less than the air it holds.

The other common kind of earmuff does the opposite job. Hearing protection uses dense cups with a soft seal to block sound, and the important number is the rating on the packet, which indicates how much noise reduction they provide. As covered on the ear day in December, noise damage is permanent and entirely preventable, and a properly fitted pair worn while using power tools or a mower is one of the cheapest pieces of health protection available.

A poor seal defeats them completely, which is why glasses arms and long hair under the cushion measurably reduce protection.

How to take part

• Wear them. Ears are where cold weather hurts first.
• Check the seal on hearing protection. A gap makes them close to useless.
• Keep a pair with the lawnmower and the power tools.
• Cover children's ears in real cold, since they lose heat faster than adults.
• Look up Chester Greenwood, who was fifteen and solved his own problem.