Hearing lets you communicate, enjoy music, notice danger, and learn from the world around you. Sound enters the ear as vibrations, and the ear changes those vibrations into signals the brain can understand. Loud sounds matter because they can injure delicate parts of the inner ear.
Protecting your hearing early helps prevent damage that may be permanent.
Key Facts
- Sound travels as vibrations called sound waves through air, liquids, or solids.
- The outer ear collects sound, the ear canal carries it inward, and the eardrum vibrates.
- Tiny ear bones amplify vibrations and send them to the cochlea.
- Hair cells in the cochlea turn vibrations into nerve signals for the brain.
- Sound level is measured in decibels, written as dB.
- A common safety rule is to keep personal audio at 60% volume or less for no more than 60 minutes at a time.
Vocabulary
- Outer ear
- The visible part of the ear that collects sound waves and directs them into the ear canal.
- Eardrum
- A thin membrane that vibrates when sound waves reach it.
- Cochlea
- A spiral-shaped inner ear structure that changes vibrations into nerve signals.
- Hair cells
- Tiny sensory cells in the cochlea that detect vibrations and can be damaged by loud sound.
- Decibel
- A unit used to measure sound intensity or loudness.
Common Mistakes to Avoid
- Ignoring ringing after a loud event is a mistake because ringing can be a warning sign that your ears were stressed or injured.
- Turning up headphones to block background noise is a mistake because it adds more sound exposure and can raise the risk of hearing damage.
- Thinking short loud sounds are always safe is a mistake because sudden noises such as fireworks or sirens can harm hearing quickly.
- Wearing earplugs incorrectly is a mistake because loose or shallow earplugs may not reduce sound enough to protect your ears.
Practice Questions
- 1 A student listens to music for 45 minutes at 50% volume. Does this follow the 60% for 60 minutes safety rule? Explain using the numbers.
- 2 At a concert, a student uses earplugs that reduce sound by 20 dB. If the sound level is 100 dB, what sound level reaches the ear after the reduction?
- 3 Explain why damage to hair cells in the cochlea can cause long-lasting hearing problems, even if the outer ear and eardrum still look normal.