Would You Rather Be Haunted by Horrible Smells or Earsplitting Sounds?

It’s a beautiful day. You’re walking through the park, surrounded by a field of flowers. But you can’t appreciate the lovely blooms. Whenever you take a breath . . . PEE-YEW! The only thing you can smell is garbage! The foul odor makes you want to vomit.      

The human nose can detect a trillion different scents—and not all of them are pleasant. Compounds that contain the element sulfur (S) are often considered particularly disgusting. They help create the instantly recognizable stink of things like rotten eggs, skunk spray, and urine.

“Some bad smells are related to safety and survival,” says Kara Hoover. She’s a biological anthropologist at the University of Alaska Fairbanks who studies how our sense of smell evolved, or changed over time. Things like rotting meat and sewage carry pathogens, like viruses and bacteria, that make us sick. Their bad smell warns us to stay away.

With each breath, odor molecules bind to receptors in the back of the nose. These cells send electrical signals to the brain, which identifies the scent and tells your body how to react. And because our sense of smell is strongly linked with our sense of taste, “getting a bad smell stuck in your nose would affect your appetite tremendously,” says Hoover.

Good luck trying to avoid an ever-present stink though. “Even if you cover your nose and breathe through your mouth, you can’t escape it,” says Hoover. Your nose and mouth are connected at the back of your throat, she explains. No matter how hard you try, “you can’t breathe without smelling.”

It’s a beautiful day. You’re walking through a field of flowers in the park. But you can’t enjoy the lovely blooms. When you take a breath . . . PEE-YEW! You can smell nothing but garbage! The foul odor makes you want to vomit.     

The human nose can detect a trillion different scents. Not all of them are pleasant. Some compounds contain the element sulfur (S). Many people find their smell disgusting. These compounds help create the stink of rotten eggs, skunk spray, and urine. Our noses instantly recognize it.

“Some bad smells are related to safety and survival,” says Kara Hoover. She’s a biological anthropologist at the University of Alaska Fairbanks. She studies how our sense of smell evolved, or changed over time. Things like rotting meat and sewage carry pathogens, like viruses and bacteria. They can make us sick. Their bad smell warns us to stay away.

We take in odor molecules with each breath. They bind to receptors in back of the nose. These cells send electrical signals to the brain. It identifies the scent and tells your body how to react. Our senses of smell and taste are strongly linked. So “getting a bad smell stuck in your nose would affect your appetite tremendously,” says Hoover.

What if a stink never left? Good luck trying to avoid it. “Even if you cover your nose and breathe through your mouth, you can’t escape it,” says Hoover. Your nose and mouth are connected at the back of your throat, she explains. No matter how hard you try, “you can’t breathe without smelling.”

It’s getting late. You’re trying to finish your homework, but you just can’t concentrate. That’s because all you can hear is an alarm going off. The loud, shrill noise is making your skin crawl and your head pound. And no matter what . . .this annoying sound won’t stop.

All sounds are produced by vibrations that cause air molecules to move back and forth. This creates sound waves that travel through the air. When sound waves reach your ear, they’re funneled down your ear canal to your eardrum. Sound waves cause this flexible membrane to vibrate. The vibrations are transformed by cells in the ear into electrical signals, which the brain interprets as sound. All sounds have different features, like duration, volume, and frequency—or number of vibrations per second, which corresponds to how high- or low-pitched a sound is.

While everyone reacts differently to sounds, “there are some that are annoying to most people,” says Sukhbinder Kumar, an auditory researcher at the University of Iowa. Scientists have found that the “worst” sounds, like a baby’s cry or a smoke alarm, often fall between 2,000 and 5,000 hertz (a unit used to measure frequency). At high volumes, these high-pitched sounds can trigger physical pain. When testing people’s reaction to a variety of different noises, Kumar found that the most-hated sound was a knife scraping against a bottle. Other unpleasant sounds included a fork dragging against a glass, the squealing brakes of a bicycle, and chalk squeaking on a blackboard.

It’s getting late. You’re trying to finish your homework, but you can’t think. All you can hear is an alarm going off. It’s loud and shrill. The noise makes your skin crawl and your head pound. And no matter what . . . this annoying sound won’t stop.

All sounds are produced by vibrations. The motion makes air molecules move back and forth. This creates sound waves that travel through the air. When sound waves reach your ear, they move down your ear canal to your eardrum. Sound waves make this flexible membrane vibrate. Cells in the ear turn the vibrations into electrical signals. Then the brain interprets the signals as sound. All sounds have different features, like duration, volume, and frequency. That’s the number of vibrations per second. It determines how high- or low-pitched a sound is.

Everyone reacts differently to sounds. But “there are some that are annoying to most people,” says Sukhbinder Kumar. He’s an auditory researcher at the University of Iowa. Scientists have found that the “worst” sounds often fall between 2,000 and 5,000 hertz (a unit for measuring frequency). Some examples are a baby’s cry and a smoke alarm. At high volumes, these high-pitched sounds can trigger physical pain. Kumar tested people’s reactions to many different noises. The most-hated sound was a knife scraping against a bottle. People also found other sounds unpleasant. These included a fork dragging against a glass, squealing bicycle brakes, and chalk squeaking on a blackboard.