Sound

• Sound


  Sound is caused by vibration (quick back and forth movement of particles). Sound is energy (in wave form) that you can hear.
• Sound waves travel fastest through solids as waves travel through particles and solids have the most tightly packed particles so they can pass on the vibrations quicker.
• Characteristics of sound waves


  • Travels at different speeds through different materials
  • Transfers energy
  • Needs a medium to travel through
• Frequency of sound waves

  The frequency of sound waves is the speed of the wave's vibration. The average human can hear sounds with frequencies between 20 and 20000 hertz.
• Volume


  Volume is measured in decibels (dB) using an oscilloscope. It means loudness: How loud or soft a sound is. Volume more than 85 dB can lead to hearing loss.
• Pitch


  The highness or lowness of a sound
• Relationship between Frequency and Pitch

  Frequency is commonly referred to as pitch of a sound

  • High frequency = High pitch
  • Low frequency = Low pitch

  There is a direct relationship between frequency and pitch
• Relationship between volume and amplitude


  Loudness/Volume depends on the amplitude of a sound

  • Large amplitude = large sound
  • small amplitude = soft sound

  There is a direct relationship between amplitude and volume
• Applications of echo examples

  • Echolocation
  • Sonar
  • Ultrasounds
• Echolocation


  Bats and dolphins use echolocation to navigate and find prey. They emit short, high-pitched sounds (dolphins make a clicking noise) that travel through water as sound waves. When these sound waves hit an object, such as a fish or rock, they bounce back as echoes. The echoes allow dolphins to create a "mental image" to help them understand their surroundings and also help them find food (they can basically interpret an object's distance, shape, size and speed as it's travelling)
• Sonar

  These are used by submarines and ships. Sonars emit sound waves underwater to detect objects, measure distances and map the ocean floor. The echoes from these waves are used to determine the location and size of objects like schools of fish, underwater mines, or other vessels.
• Ultrasounds

  In healthcare, ultrasound uses high-frequency sound waves to create images of internal organs, muscles and also unborn babies. The sound waves bounce off tissues within our bodies and are captured as echoes which sonographers use to form images.