Snell’s law governs how sound bends across temperature boundaries.

Evidence

Consider the situation shown in Figure 1.19 where there is a boundary between air at two different temperatures. When a sound wave approaches this boundary at an angle, the direction of propagation will alter according to Snell’s law, that is, using Equation 1.5: where θ1, θ2 = the propagation angles in the two media cT1, cT2 = the velocities of the sound waves in the two media and T1, T2 = the absolute temperatures of the two media Thus the change in direction is a function of the square root of the ratio of the absolute temperatures of the air on either side of the boundary. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 332

Categorization

• DEFINE: Names Snell’s law as the rule governing acoustic refraction across temperature boundaries.