Sound but no Sight
Classical Mechanics
Level
2
Two people--Andy and Bran--are standing far apart in an open field, and Andy is shouting at Bran. When Caleb walks in between Andy and Bran, Bran is no longer able to see Andy but is still able to hear Andy. How is this possible?
Humans absorb light but not sound
The size of a human is comparable to the wavelength of sound
Light travels in a straight line but sound does not
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1 solution
Diffraction of sound waves occurs when a sound wave encounters an object which has a size comparable to the wavelength of the sound wave. Because of this phenomenon, the sound waves bend around the edges of the obstacle (in this case, Caleb) to the reach Bran's ears. This is why Bran is still able to hear Andy.