After an exciting three-hour concert by her favorite Norwegian metal band, Anja notices something strange. She can barely hear her friend talking about the show. It feels like he’s speaking from far away, and there’s a constant ringing in her ears. By the next morning, her hearing is mostly back to normal, but Anja still wonders: What caused this? Will her hearing fully recover? And can she keep going to concerts without hurting her ears?
To answer these questions, we need to understand what sound is and how we hear it. Sound is created when molecules move and vibrate through the air. Our ears are specially designed to pick up these vibrations. Sound waves enter our ear canals and hit the eardrum. Then, three tiny bones called the ossicular chain carry these vibrations into the cochlea, a spiral-shaped part of the inner ear. Here, the vibrations turn into waves of fluid, which move a membrane lined with thousands of tiny hair cells. These hair cells help our brain understand the sounds we hear.
Unfortunately, these hair cells are delicate and can be damaged by two main things: volume and duration. The louder a sound is, the more pressure it puts on these cells. If a sound is over 120 decibels, like a jet engine, it can instantly damage the hair cells, leading to permanent hearing loss. Loud sounds can even dislocate the tiny bones in the ear or burst the eardrum.
The length of time you’re exposed to sound also matters. Even sounds that aren’t extremely loud can harm your ears if you listen to them for too long. For example, a hand dryer is safe for a short time, but listening to it for hours could overwork the hair cells, making your hearing muffled. This temporary hearing loss is called a temporary threshold shift, and it’s what Anja experienced at the concert. Luckily, this kind of hearing loss usually goes away as the hair cells recover.
While one temporary threshold shift isn’t likely to cause permanent damage, frequent exposure to loud sounds can lead to problems like tinnitus, a constant ringing in the ears, or trouble understanding speech in noisy places. Overworked hair cells can also produce harmful molecules that damage the inner ear permanently.
To protect your hearing, there are several things you can do. If you use earbud headphones, keep the volume at 80% or lower if you’re listening for more than 90 minutes a day. Noise-isolating headphones can help you listen at lower volumes too. It’s also important to get your hearing checked regularly, just like you would with your eyes or teeth. If you don’t have access to an audiologist, there are portable hearing tests and apps available to help.
Finally, when you’re in loud environments, like concerts, wear earplugs. Make sure to insert them correctly for the best protection. With these precautions, you can continue enjoying your favorite music without risking your hearing.
Conduct an experiment to visualize sound waves. Fill a bowl with water and gently tap the surface with a tuning fork. Observe the ripples created and discuss how these represent sound waves traveling through the air. Consider how different frequencies might affect the ripples.
Use a smartphone app to measure the decibel levels of various sounds around you, such as a classroom, a busy street, and music played through headphones. Record your findings and discuss which sounds are safe and which could potentially harm your hearing over time.
Design and create a simple pair of earplugs using materials like foam or cotton. Test their effectiveness by measuring sound levels with and without your earplugs in a controlled environment. Discuss how well they protect your ears and what improvements could be made.
Engage in role-playing scenarios where you practice explaining the importance of hearing protection to a friend who frequently attends loud concerts. Focus on effective communication and persuasion techniques to encourage safe listening habits.
Create a poster or digital presentation to raise awareness about the importance of hearing protection. Include facts about how loud sounds can damage hearing and tips for protecting your ears. Share your campaign with classmates or on social media to spread the message.
After a three-hour concert by her favorite Norwegian metal band, Anja finds it difficult to hear her friend rave about the show. It sounds like he’s speaking from across the room, and it’s tough to make out his muted voice over the ringing in her ears. By the next morning, the effect has mostly worn off, but Anja still has questions. What caused the symptoms? Is her hearing going to fully recover? And can she still go to concerts without damaging her ears?
To answer these questions, we first need to understand what sound is and how we hear it. Sound is created when displaced molecules vibrate through space. While sound vibrations can travel through solids and liquids, our ears have evolved to process vibrations in the air. These waves of air pressure enter our ear canals and bounce off the eardrum. A trio of bones called the ossicular chain then carries those vibrations into the cochlea, transforming waves of air pressure into waves of cochlear fluid. Here, our perception of sound begins to take form. The waves of fluid move the basilar membrane, a tissue lined with tens of thousands of hair cells. The specific vibration of these hair cells and the stereocilia on top of each one determine the auditory signal our brain perceives.
Unfortunately, these essential cells are also quite vulnerable. There are two properties of sound that can damage these cells. The first is volume. The louder a sound is, the greater the pressure of its vibrations. While the ear’s upper limits vary from person to person, close-range exposure to sound exceeding 120 decibels can instantly damage hair cells, resulting in permanent hearing loss. The pressure of more powerful sounds can even dislocate the ossicular chain or burst an eardrum.
The other side of this equation is the sound’s duration. While dangerously loud sounds can injure ears almost instantly, hair cells can also be damaged by exposure to lower sound pressure for long periods. For example, hearing a hand dryer is safe for the 20 seconds you’re using it. But if you listened for 8 consecutive hours, this relatively low-pressure sound could overwork the stereocilia and swell the hair cell’s supporting tissue. Swollen hair cells are unable to vibrate with the appropriate speed and accuracy, making hearing muffled. This kind of hearing loss is known as a temporary threshold shift, and many people will experience it at least once in their lifetime. In Anja’s case, the loud sounds of the concert only took three hours to cause this condition. Fortunately, it’s a temporary ailment that usually resolves as swelling decreases over time. In most cases, simply avoiding hazardous sounds gives hair cells all they need to recover. One temporary threshold shift isn’t likely to cause permanent hearing loss.
However, frequent exposure to dangerous sound levels can lead to a wide range of hearing disorders, such as the constant buzz of tinnitus or difficulty understanding speech in loud environments. Overworked hair cells can also generate harmful molecules that can cause permanent damage to the inner ear.
There are numerous strategies you can adopt for preventing hearing loss. Current research around earbud headphone use suggests keeping your volume at 80% or less if you’ll be listening for more than 90 minutes throughout the day. Noise-isolating headphones can also help you listen at lower volumes. Getting a baseline understanding of your hearing is essential to protecting your auditory system. Just like our eyes and teeth, our ears also need annual check-ups. Not all communities have access to audiologists, but organizations around the world are developing portable hearing tests and easy-to-use apps to bring these vital resources to remote regions. Finally, wear earplugs when you’re knowingly exposing yourself to loud sounds for extended periods. An earplug’s effectiveness depends on how well you’ve inserted it, so be careful to read the instructions. But when worn correctly, they can ensure you’ll be able to enjoy your favorite band for many nights to come.
Sound – Vibrations that travel through the air or another medium and can be heard when they reach a person’s or animal’s ear. – The sound of the teacher’s voice was clear and easy to understand during the biology lecture.
Hearing – The ability to perceive sound by detecting vibrations through the ear. – Hearing is an essential sense that allows us to enjoy music and communicate with others.
Cells – The basic structural, functional, and biological units of all living organisms. – The human body is made up of trillions of cells, each performing specific functions necessary for life.
Damage – Harm or injury that reduces the value or usefulness of something. – Prolonged exposure to loud noises can cause damage to the delicate cells in the inner ear.
Volume – The degree of loudness or intensity of a sound. – Listening to music at a high volume for extended periods can lead to hearing loss.
Concert – A live music performance in front of an audience. – Attending a rock concert without ear protection can expose you to dangerously high sound levels.
Tinnitus – A condition characterized by ringing or buzzing in the ears. – After the loud concert, she experienced tinnitus, which made it difficult to concentrate.
Pressure – The continuous physical force exerted on or against an object by something in contact with it. – Changes in air pressure can affect the ears, causing discomfort during a flight.
Protection – Measures taken to guard against harm or injury. – Wearing earplugs provides protection against hearing damage in noisy environments.
Music – Vocal or instrumental sounds combined in such a way as to produce beauty of form, harmony, and expression of emotion. – Music can have a calming effect on the mind and body, promoting relaxation and well-being.
