In fact, when the wavelength of the waves are smaller than the obstacle, no noticeable diffraction occurs. Diffraction of water waves is observed in a harbor as waves bend around small boats and are found to disturb the water behind them. The same waves however are unable to diffract around larger boats since their wavelength is smaller than the boat. Diffraction of sound waves and of light waves will be discussed in a later unit of The Physics Classroom. Reflection, refraction and diffraction are all boundary behaviors of waves associated with the bending of the path of the wave.
Reflection occurs when there is a bouncing off of a barrier.
Reflection of waves off straight barriers follows the law of reflection. Reflection of waves off parabolic barriers results in the convergence of the waves at a focal point.