Sound Waves
A sound wave is a vibration created by energy moving through a medium, like air, spreading from its source. Discover how sound travels and resonates.
As sound passes through the air, the air particles move left and right due to the energy of the sound wave passing through it. It's the vibrating air particles that cause the human eardrum to vibrate, which the brain then interprets as sound.
Partical Movement
- Local Movement: Air molecules do not travel from the noise source to the ear. Each individual molecule only moves a small distance as it vibrates.
- Ripple Effect: This local movement causes adjacent molecules to vibrate in a rippling effect all the way to the ear.
Transverse waves vibrate at 90 degrees to the direction of the wave. In contrast, longitudinal waves have vibrations along the same axis as the direction in which the wave is traveling. Think of the way a slinky behaves if two people are holding each end and one person quickly sends a number of vibrations down it.
Compression happens in the region in a longitudinal wave where the particles are closest together. Rarefaction is a region in a longitudinal wave where the particles are farthest apart.
Sound waves are longitudinal, and should not be confused with transverse waves. Light waves and the ripples we see on water are examples of transverse waves.
Key Characteristics
- Frequency: This refers to the number of vibrations or cycles per second, measured in Hertz (Hz). Higher frequency sounds are perceived as higher pitches.
- Wavelength: The distance between two successive points that are in phase (e.g., from crest to crest or trough to trough). Wavelength is inversely related to frequency.
- Amplitude: This is the height of the wave, which determines the loudness of the sound. Higher amplitude means a louder sound.
- Velocity: The speed at which a sound wave travels through a medium depends on the medium's properties, like density and elasticity. For instance, sound travels faster in water than in air.