Refraction

• Speed and wave length is reduced but frequency stays the same and the wave changes direction
• Mechanical waves slow down when they pass from a denser to a rarer material and vice versa
• Electromagnetic waves like light increase in speed from an optically denser to a rarer medium.
• When wave is slowed down, it is refracted towards normal (i > r)
• When wave is sped up, it is refracted away from normal (i < r)
• Deep water is denser than shallow water

  
• Shallow water to deep water: speed increases wavelength increases, and frequency remains constant

  
• Deep water to shallow water: speed decreases, wavelength decreases, and frequency remains constant