The scientific principle that describes the relationship between frequency and wavelength is known as the wave equation, typically expressed as c = fλ, where c is the speed of light, f is frequency, and λ (lambda) is wavelength. This principle reveals that as the frequency of a wave increases, its wavelength decreases, and vice versa. It is fundamental in fields such as physics, optics, and acoustics, influencing our understanding of light, sound, and other wave phenomena.