Science in English – Forces And Energy (Sound)
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- When an object vibrates, such as vocal chords, the vibrations push the surrounding molecules in every direction. A medium is composed of molecules and can be solid, liquid, or gas. A medium is necessary for sound energy to be moved from one place to another because the sound travels by pushing molecules into each other in all directions emanating from the source, sort of like dominoes.
- Sound energy travels out in all directions through a medium from the sound source.
- Sound wavesare typically used to show how sound can travel in a particular direction and can be used to capture pitch and volume.
- Vibrations diminish over a distance. Loudness diminishes over a distance.We measure sound in decibels.
- Vibrations “cause” sound that we can hear. The harder the force to begin the vibration,the louder the soundand the more energy it has(wave amplituderepresents volume)
- Sounds travel through air to our ears.
- The outer ear directs sound waves into ear canal
We hear with our ears. Soundwaves make the eardrum vibrate. The ossicles carry the vibration to the cochlea. Fluid inside the cochlea makes tiny hairs vibrate and send signals to the brain. We have two ears to help us judge the direction of a sound. A stethoscope amplifies the sound from the heart. A microphone changes sound waves into electrical signals.
- A sound can be loud or soft.
- Small vibrations produce quiet
- a ruler makes a louder sound when you flick it harder so that it moves further to and fro.
- Sounds that spoil the environment are called sound pollution.
- Aircraft noise / noise from a construction site is one example of sound pollution.
- The loudness of sounds is measured in decibels
- The sound of people talking quietly is about 40 decibels, noisy traffic is 80 decibels, a loud pop concert is 100 decibels, and a jet aircraft nearby is 130
- People working in noisy environment must wear ear protectors