ST: M3-M5

• What causes sound?


  Sound is caused by vibrations, which are the back and forth movement of objects.
• How do sound waves reach your ear?


  Sound waves reach your ear when vibrations produced by an object travel through a medium.
• What type of waves are sound waves?


  Sound waves are longitudinal waves where the vibrations are parallel to the direction of the wave.
• What is required for sound waves to propagate?


  Sound waves need a medium to propagate.
• In which medium do sound waves travel fastest?


  Sound waves travel fastest in solids.
• What factors affect the speed of sound?


  The speed of sound is affected by the elasticity and density of the medium.
• What is elasticity in the context of sound propagation?


  Elasticity is the ability of a material to return to its original form after a force has been applied.
• Why does sound travel faster in more elastic materials?


  Sound travels faster in more elastic materials because their atoms and molecules respond faster to each other's movement.
• How does the speed of sound differ in solids, liquids, and gases?


  Sound travels fastest in solids, followed by liquids, and slowest in gases.
• What happens when you talk to someone 100 meters away using air as the medium?


  You would have to shout to be heard.
• How does density affect the speed of sound?


  Denser objects have more compact atoms and molecules, making sound waves travel slower.
• What is the speed of sound in dry air at 0°C?


  The speed of sound in dry air at 0°C is around 331 m/s.
• How does temperature affect the speed of sound in air?


  The speed of sound increases with temperature, particularly in the presence of water vapor.
• How much does the speed of sound increase with every 1°C rise in temperature?


  The speed of sound increases by 0.60 m/s for every 1°C rise in temperature.
• What is the formula to calculate the speed of sound in air based on temperature?


  The formula is $v =$$331 \text{ m/s} +$$(0.6 \text{ m/s} \degree C) \cdot T$.
• What is refraction in the context of sound waves?


  Refraction is the change in direction of sound waves as they pass from one medium to another.
• How does temperature affect the refraction of sound waves?


  Sound waves travel slower in cooler air than in warmer air, affecting their direction.
• What happens to sound waves during the day compared to at night regarding refraction?


  During the day, sound travels faster at the earth's surface and refracts upward; at night, it travels faster at higher altitudes and is refracted downward.
• What are the properties of sound waves when they encounter obstacles?


  • Sound waves undergo reflection and refraction.
  • Reflection is the turning back of the wave when it hits a barrier.
  • Echo is an example of reflected sound.
  • Reverberation refers to multiple reflections in a space.
• What are some applications of sound reflection?


  • Echo sounding to map the seafloor.
  • Bats use sound reflection to detect distances.
  • Reverberation management in theaters using curtains and carpets.
• What factors affect the speed of sound in different media?


  • Elasticity: More elastic materials allow faster sound travel.
  • Density: Denser materials slow down sound travel.
  • Temperature: Higher temperatures increase sound speed.