Waves

Waves

1. Two Types

   • Transverse
     • All transverse waves have peaks and troughs
     • Transverse waves are waves that oscillate 90° to the direction of travel
   • Longitudinal
     • Longitudinal waves are waves that oscillate in the same direction of travel

2. The wavelength of a wave is the length of one complete wave. The unit of wavelength is the metre

3. The frequency of a wave is the number of oscillations per unit time. The frequency of a wave is the same as the frequency of the source that produces the wave. The unit of frequency is the hertz.

4. The period of a wave is the time that it takes for one complete oscillation. The unit of period is the second.

5. The speed (v) of a wave is the distance travelled per unit time by the wave. The unit of speed is the metre per second, m s-1.

6. The speed, frequency and wavelength of a wave are linked by the following relationship,

7. Reflection

   • Reflection occurs when a wave bounces from the surface of an obstacle. None of the properties of a wave are changed by reflection. The wavelength, frequency, period and speed are same before and after reflection. The only change is the direction in which the wave is travelling.

8. Refraction

   • Refraction occurs when a wave moves from one material to another. The speed and wavelength are changed by refraction. The frequency and period of the wave stay the same. The direction in which the wave is travelling may or may not be changed by refraction.

9. The Wave Equation

10. Important Infomation

11. The amplitude of a wave is the distance from the rest position to maximum peak or minimum trough

12. Seismic Waves

    • Seismic waves travel through the layers of the Earth. They usually result from an earthquake, volcanic eruption or other explosion
    • There are two types of seismic waves – P waves and S waves
      • P-waves are longitudinal, therefore they can pass through the outer core (liquid)
        • They travel around 3-5 km/s
      • S-waves are transverse, therefore they cannot pass through the outer core (liquid)

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