Wave scattering behavior is governed by object size relative to wavelength

Evidence

Sound that is incident on an object is not just diffracted around it—some of the incident energy will be reflected, or scattered, from the side facing the incident wave, as shown in Figure 1.47. As in the case of diffraction, it is the size of the object with respect to the wavelength that determines how much and in what way the energy is scattered. When the object is large with respect to the wavelength, most of the sound incident on the object is scattered according to the laws of reflection, and there is very little spreading or diffraction of the reflected wave, as shown in Figure 1.48. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 435

Categorization

• XREF: This object-size-versus-wavelength rule recurs across acoustics, optics, and antenna physics; ties to the two-thirds wavelength threshold appearing throughout the chapter.
• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 435