P2.Waves

• What is a common behavior of waves?

  Waves carry energy and information
• Why is understanding mechanical waves important?

  For designing safe and comfortable structures
• What types of waves are there?

  Transverse and longitudinal waves
• What is an example of a transverse wave?

  Ripples on a water surface
• What type of wave are sound waves in air?

  Longitudinal waves
• What do longitudinal waves show?

  Areas of compression and rarefaction
• What travels in waves rather than the medium itself?

  The wave itself, not water or air
• What are the key properties of waves?

  Amplitude, wavelength, frequency, period
• What is the amplitude of a wave?

  Maximum displacement from undisturbed position
• How is wavelength defined?

  Distance from one wave point to the next
• What does frequency measure?

  Number of waves passing a point each second
• What is the formula for period?

  Period = $\frac{1}{frequency}$
• What is the wave speed equation?

  Wave speed = frequency × wavelength
• How can students identify amplitude and wavelength?

  From given diagrams
• What is a method to measure sound wave speed?

  1. Two people stand a distance of around 100 m apart
  2. The distance between them is measured using a trundle wheel
  3. One person has two wooden blocks, which they bang together above their head
  4. The second person has a stopwatch which they start when they see the first person banging the blocks together and stops when they hear the sound
  5. This is then repeated several times and an average value is taken for the time
  6. The speed of sound can then be calculated using the equation Speed of sound = Distance Travelled by Sound /Time taken
• What is a method to measure ripple speed?

  Describe a method to measure on water
• How are changes in velocity, frequency, and wavelength related?

  They are inter-related in sound wave transmission
• What happens to waves at material boundaries?

  Waves can be reflected, absorbed, or transmitted
• What should students be able to illustrate with ray diagrams?

  The reflection of a wave at a surface
• What is the effect of reflection, transmission, and absorption?

  They occur at material interfaces
• How do sound waves travel through solids?

  They cause vibrations in the solid
• What happens to sound waves in the ear?

  They cause the ear drum to vibrate
• What is the range of normal human hearing?

  20 Hz to 20 kHz
• How are ultrasound waves used in detection?

  They are partially reflected at boundaries
• What do seismic waves provide evidence for?

  The structure and size of the Earth’s core
• What are P-waves and S-waves?

  P-waves are longitudinal; S-waves are transverse
• How is echo sounding used?

  To detect objects in deep water
• What is the nature of electromagnetic waves?

  They are transverse waves that transfer energy
• How do electromagnetic waves travel in a vacuum?

  All types travel at the same velocity
• What groups are in the electromagnetic spectrum?

  Radio, microwave, infrared, visible light, ultraviolet, X-rays, gamma rays
• What do our eyes detect in the electromagnetic spectrum?

  Only visible light
• How do different substances interact with electromagnetic waves?

  They may absorb, transmit, refract, or reflect waves
• What is refraction caused by?

  Difference in velocity of waves in substances
• What should students be able to illustrate with ray diagrams?

  The refraction of a wave at a boundary
• What do wave front diagrams explain?

  Refraction in terms of wave speed change
• What are the key properties of waves?

  • Amplitude
  • Wavelength
  • Frequency
  • Period
• What are the key opportunities for skills development in this content?

  • WS (Working Scientifically)
  • MS (Mathematical Skills)
  • AT (Assessment Techniques)
• What can different substances do with electromagnetic waves?

  Absorb, transmit, refract, or reflect
• What causes refraction in waves?

  Difference in velocity in different substances
• How can students illustrate the refraction of a wave?

  By constructing ray diagrams