Sound

• Experiment 1: Measuring the Speed of Sound Between Two Points
• Aim: Measure the speed of sound in air between two points
• Variables:

  • Independent variable = Distance
  • Dependent variable = Time
  • Control variables: Same location to carry out the experiment
• Method:

  • Use the trundle wheel to measure a distance of 100 m between two people
  • One person bangs two wooden blocks together to generate sound waves
  • The second person uses a stopwatch to time the sound waves
  • Repeat for various distances and calculate the average time
• Analysis:

  • The speed of sound can be calculated using the equation provided
  • The speed of sound in air should be around 340 m/s
• Experiment 2: Measuring the Speed of Sound with Oscilloscopes
• Aim: Measure the speed of sound in air between two points using an oscilloscope
• Variables:

  • Independent variable = Distance
  • Dependent variable = Time
  • Control variables: Same location to carry out the experiment, same set of microphones for each trial
• Method:

  • Connect two microphones to an oscilloscope
  • Place them about 2 m apart
  • Set up the oscilloscope to trigger when the first microphone detects a sound
  • Measure the time difference between the two microphones for different distances
• Pitch & Loudness
• Pitch:

  • Related to the frequency of the vibrating source of sound waves
  • High frequency = high pitch, low frequency = low pitch
• Loudness:

  • Related to the amplitude of the vibrating source of sound waves
  • Loud sound = large amplitude
• Range of Human Hearing:

  • Human ear responds to vibrations caused by sound waves
  • Frequency range for human hearing is 20 Hz to 20,000 Hz