Wake Angle of a Duck Consider this duck: Via: Goodstock Images and this one: Via: Ted Soqui (Getty Images) And these ones: Via: United States Navy All very different types of ducks, but all share one thing in common: the angles of their wakes are all identical. This is because objects moving through sufficiently deep water always exhibit the same wake angle regardless of size, shape, or velocity. This phenomenon was first studied by Lord Kelvin in 1887. Lord Kelvin was, among other things, an avid sailor, who noticed that the angles of wakes produced by his boats was always 19.5 degrees when traveling at a constant speed irrespective of any other factors. The mathematical proof that Lord Kelvin presented for this is far beyond the scope of this project. It is essentially caused by the duck constantly producing waves of the same wavelength and same velocity because it is traveling at a constant rate. Since the waves produced travel outward at a constant speed that is relative to the speed of the duck, this forms a triangle whose sides are always the same proportion and is therefore similar in all cases, producing the Kelvin wake angle of 19.48 degrees. This explanation alone is insufficient to model the wake, because it does not account for the waves inside and outside of the wake. The wake is produced by constructive interference of the wavelengths produced by the duck, and the other waves are destroyed by destructive interference. The mathematical model of this is again far too complicated for this project.