# Translations:Huygens’ principle/5/en

Huygens’ principle embodies a simple but powerful physical concept that serves to explain in a lucid manner how an arbitrary wavefront progresses from one point to another (Robinson and Clark, 2006b^{[1]}). According to this hypothesis, each individual point on an advancing wavefront is disturbed. It therefore acts as a source of a distinct expanding disturbance of its own. Thus, each point of the wavefront at time *t* excites a secondary spherical wavelet that travels outward in all directions from this point. At a later instant , the new composite wavefront is the summation of the separate effects of all the wavelets originating in the earlier wavefront at the earlier time *t*. Graphically, the advanced wavefront is the envelope of all the individual wavelets. Figure 10 shows three examples of such summations.

- ↑ Robinson, E. A., and R. D. Clark, 2006b, Huygens’ principle: The Leading Edge, 25, no. 10, 1252–1255.