Vibrations And Sound

  • Sound is produced through vibration, moves in all directions and can be reflected. These qualities provide many benefits to human beings when used properly. Sound helps life to communicate with each other.
6.1  Vibrations And Sound
  • Sound is produced by vibration from the source

  • Sound can be produced in several ways such as:
  1. When the flute is blown, the air inside the flute vibrates
  2. When the xylophone is knocked, the xylophone bar vibrates
  3. When the strings of the guitar or violin are plucked or bowed, they vibrate.
  4. The cymbal pieces will vibrate when clapped together

Sounds travel

  • Despite being in different positions, they could hear the sound of the police car siren because of the sound waves moving in all directions
Sound can be reflected
  • When sound hits a hard surface, it will be reflected back

  • Example of sound reflection is in the picture above:
  1. Screaming in the cave
  2. Screaming in the empty hall
Sound reflection phenomenon
  • An echo is a sound produced when sound is reflected on a hard surface.

  • Ultrasound is a sound that cannot be heard by humans but can be heard by animals such as bats, dolphins and whales to guide and track the location of their respective prey.
  • In medicine, ultrasonic sound reflection is used to detect organs in a patient’s body or fetus in the womb.

  • Sonar is an ultrasonic sound reflection technology used to detect objects in water.
Useful and harmful sounds
  • The benefits of sound to everyday life:
  1. Sound allows us to communicate
  2. Musical sound can be entertaining
  3. An ambulan siren indicates emergency alert
  4. Phone ringing provides notification on incoming calls
  • Sound loudness is measured in decibels (dB). Loud noises that exceeds 85 dB can damage our hearing.
  • Harmful noise, for example:
  1. The noisy environment makes it difficult to communicate
  2. Excessive noise can cause disturbance and stress
  3. Frequent or excessive loud noise can cause hearing problems
Reducing sound pollution
  • Noise that is too loud or unwanted can be reduced to be quieter or less clear.
  • Situations and ways to reduce noise pollution:
  1. Airport ground staff use ear protectors to protect ear damage from the excessive aircraft noise.
  2. Sound absorbers such as carpets, curtains and windows can reduce sound vibration.
  3. The use of trees can help reduce noise pollution in our environment.