Zusammenfassung der Ressource
Sound
- Is made by vibrations.
- Amplitude and Frequency
- Loud sounds are made by large amplitude vibrations.
- Quiet sounds are made by amplitude vibrations.
- A high pitch is made by a high (fast) frequency.
- Low pitched sounds are made by low frequency (slow) vibration.
- We can observe amplitude and frequency of sound waves using an oscilloscope. Frequency is measured in hertz.
- Loudness
- Loudness is measured in decibels.
- Loud sounds can cause deafness.
- Loud sounds are sometimes called noise pollution.
- How Sound Travels
- Sound cannot travel in a vacuum because there are no particles.
- Sound travels fast in gases like air.
- Sound travels faster in liquids like water.
- Sound travels even faster in solids like steel.
- But light travels a million times faster than sound.
- Sound Range
- Sound is heard by ears.
- Vibrations of the eardrum are converted into electrical signals, which travel to the brain.
- Most people can hear sounds between 20Hz and 20000Hz.
- Older people cannot hear some
high pitched sounds.