<span>"Time is like wax, dripping from a candle flame. In the moment, it is molten and falling, with the capability to transform into any shape. Then the moment passes, and the wax hits the table top and solidifies into the shape it will always be. It becomes the past, a solid single record of what happened, still holding in its wild curves and contours the potential of every shape it could have held."</span>
The frequency of a wave is the number of complete oscillations passing a given point per second.
In this case, assuming the duck is stationary, we have 4 complete waves passing the duck in one second: therefore, the frequency of the wave is