Wave measurements

• What should you know after studying this topic?

  How to calculate frequency from the period of a wave, measure wavelength and frequency in a ripple tank, calculate wave speed, and measure the speed of sound in air.
• What is the period of a wave?

  The period of a wave is the time taken for one complete wave to pass a fixed point.
• If a point on a transverse wave takes 5 seconds to oscillate, what is the time period of the wave?

  The time period of the wave is 5 seconds.
• How are the period and frequency of a wave related?

  The period and frequency of a wave are linked; frequency is the inverse of the period.
• How do you calculate the frequency of a wave if the period is known?

  You divide 1 by the period.
• Given a period of 5 seconds, what is the frequency of the waves in the sea?


  The frequency is 0.2 Hz.
• What is the first step in investigating wave speed in a ripple tank?

  Set up the ripple tank as shown in the provided figure.
• What should you use to measure the wavelength in a ripple tank experiment?

  Measure the distance between five peaks on the photo and divide by 4.
• How can you measure the frequency of waves in a ripple tank?

  Video the waves and the stopwatch, then divide 10 by the recorded time for 10 waves.
• What is the procedure to measure the speed of sound in air?

  Stand 200m apart, time the interval between seeing and hearing cymbals crash, and calculate the speed using distance and time.
• If it takes 0.59 seconds for sound to travel 200 meters, how do you calculate the speed of sound?

  Use the equation speed = distance / time.
• What is the actual speed of sound in air?

  340 m/s.
• Why might the calculated speed of sound differ from the actual speed of sound in air?

  Possible errors in timing or environmental factors could affect the results.
• What is the purpose of taking a photograph of the waves in a ripple tank?

  To measure the wavelength of the waves.
• What should you do to determine the frequency of waves in slow motion?

  Record the waves in slow motion and measure the time for 10 waves to pass a fixed point.
• What is the method to calculate the wavelength from the distance between peaks in a ripple tank?

  Measure the distance between five peaks and divide by 4.
• What data is shown in the results table for the experiment?

  The table shows the distance between peaks, time for waves, period, frequency, and wave speed.
• How do you calculate the average time interval from multiple measurements?

  Add the time intervals together and divide by the number of measurements.
• What happens to wave speed and wavelength when frequency is decreased?

  As frequency decreases, wave speed and wavelength typically increase.