Measuring Sound
Sound is a pressure wave caused when something vibrates, making particles bump into each other and then apart. The particles vibrate back and forth in the direction that the wave travels but do not get carried along with the wave.
When you clap your hands, you force air particles together and then apart. This effect ripples out and away from your hands as a small group of sound waves. The particles close to your hands are pushed outwards and bump into neighboring particles, and these then move and bump into more particles. The effect is very much like dropping a stone into a pool of water and causing a ripple pattern (sound waves) extending outwards from the original source (your clapping hands).
Similar to water ripples, pressure waves move outwards from the sound source. These changes in particle spacing are also changes in pressure. Pressure increases when particles are squeezed together and reduces when they move apart. It is these changes in pressure that can be detected by organs such as the human ear and are sensed as sound.
Sound is measured in two ways: decibels and frequency.
Decibels measure the pressure of sound. Frequency is related to a sound’s pitch and is measured in units called hertz (Hz), or cycles per second. The pitch of a sound — how high or low it seems — is how you perceive its frequency; the higher the pitch, the higher the frequency. High-frequency sounds are generally more annoying than low-frequency sounds and can be more harmful to hearing.
Human hearing is most sensitive to frequencies between 3,000 and 4,000 Hz. That’s why people with damaged hearing have difficulty understanding higher-pitched voices and other sounds in the 3,000 to 4,000 Hz range.
Check out the CDC Noise Meter page to get a better idea of how “loud” is loud.
Sound is a pressure wave caused when something vibrates, making particles bump into each other and then apart. The particles vibrate back and forth in the direction that the wave travels but do not get carried along with the wave.
When you clap your hands, you force air particles together and then apart. This effect ripples out and away from your hands as a small group of sound waves. The particles close to your hands are pushed outwards and bump into neighboring particles, and these then move and bump into more particles. The effect is very much like dropping a stone into a pool of water and causing a ripple pattern (sound waves) extending outwards from the original source (your clapping hands).
Similar to water ripples, pressure waves move outwards from the sound source. These changes in particle spacing are also changes in pressure. Pressure increases when particles are squeezed together and reduces when they move apart. It is these changes in pressure that can be detected by organs such as the human ear and are sensed as sound.
