A mysterious humming sound in Windsor, Canada, has finally stopped, Canadian Broadcasting Corporation (CBC) reported. A U.S. Steel plant is to blame for the sound that annoyed the Great Lakes town for nearly a decade. Hearing is a delicate and intricate process.
As the CBC reported, the town of Windsor—which neighbors Michigan near Detroit—has one fewer concern on its hands. “The mysterious, low-frequency noise that plagued the city of Windsor for nearly a decade has finally quieted down after a steel factory just outside neighboring Detroit halted its operations indefinitely,” the article said.
“The so-called ‘Windsor Hum’ has been the subject of intense speculation by governments and journalists on both sides of the Canada-U.S. border since 2011, when an investigation by the Canadian government first documented its existence. Although the origin of the hum was initially up for debate, research in recent years pinpointed the culprit as a U.S. Steel facility on Zug Island, just across the river from Windsor’s west end.”
Windsor residents are sure to be happy the sound is no longer assaulting their ears. The anatomy of our ears and how they hear is fascinating.
In One Ear
The journey of hearing goes from the outside in, so it makes sense to look at our ears in the same direction.
“Our ears are crescent-shaped knobs fixed to the sides of our heads, each fashioning an inner fold leading to a mysterious tunnel,” said Dr. Indre Viskontas, Adjunct Professor of Psychology at the University of San Francisco and Professor of Sciences and Humanities at the San Francisco Conservatory of Music. “This outer region is called the pinna, and pinnas act as sound collectors, capturing and funneling sound waves into the ear for better hearing. Pinnas are helpful for localizing the source of sounds in space as well as for our sensitivity to sounds that are very faint.”
The tunnel in the pinna, the ear canal, leads to the middle ear, ending at the eardrum. Dr. Viskontas said the eardrum is exactly what it sounds like—a circular membrane sheet. The high tension and thinness of the eardrum make it sensitive to changes in air pressure.
“Attached to the back of the eardrum are three of the most extraordinary bones in our bodies,” Dr. Viskontas said. “The malleus, incus, and stapes are better known as the hammer, anvil, and stirrup because that’s exactly what they look like. Their purpose is to link the eardrum to [another membrane called] the ‘oval window.'”
The hammer, anvil, and stirrup are called the ossicular bridge. This unique structure—the eardrum, the ossicular bridge, and the oval window—makes for a delicate and intricate hearing system.
According to Dr. Viskontas, the complexity and development of those three tiny ear bones—each of which are about the size of a single letter typed in 12-point type size, she said—came a long way. In fact, they came from ancestral fish.
“When we lived in the oceans, the sounds that we heard were dampened, literally, by water. Sound travels differently in water, because the molecules that are disturbed by sound waves in water are packed more densely than those in the air. Sound waves require more force in water than in air to travel the same distance, even though sound travels faster in water than in air.”
Dr. Viskontas said sound travels by disturbing molecules, and since molecules in air are farther apart than in water, it takes longer for the molecules to collide and make sound waves in air—but it’s harder to start the sound waves in water.
“Mother Nature is a tinkerer, not a designer, so we’ve kept one portion of our aquatic ears—beyond the oval window, the inner ear is filled with fluid,” she said. “In order to hear the crunching of leaves beneath the feet of a lion, or the movement of a snake in a tree, our middle ear evolved the ossicular bridge as an amplification system.”
Finally, the oval window connects to the cochlea, which Dr. Viskontas referred to as “our organ for hearing” or “our eyeball for sound,” adding that it looks like a fluid-filled windsock, rolled up like a snail’s shell. The cochlea contains several thousand “hair cells,” which look like very small hairs standing on end. The motion of the fluid in the cochlea, which came from the oval window, causes the hair cells to move and permit negatively or positively charged molecules in the cell gates.
We interpret these molecules as sound.
Dr. Indre Viskontas contributed to this article. Dr. Viskontas is an Adjunct Professor of Psychology at the University of San Francisco and Professor of Sciences and Humanities at the San Francisco Conservatory of Music, where she is pioneering the application of neuroscience to musical training. Professor Viskontas received her Bachelor of Science degree with a Specialist in Psychology and a minor in French Literature at Trinity College in the University of Toronto. She also holds a Masters of Music degree in vocal performance from the San Francisco Conservatory of Music. She completed her PhD in cognitive neuroscience at the University of California, Los Angeles.