People hear various kinds of sounds everyday, such as music, creatures’ voices and even ourselves’ breathing. Lots of people would like to enjoy music by their earphones instead of by their phones, for the echo of earphones is better, which is the reflection of sound.
Most sounds are waves produced by the vibration of matter. And sound energy is carried by the transmitted wave. For example, after striking a tuning fork, put that fork into the basin, which is full of water. There are waves that spread out from the vibrating tuning fork in the water. Then the waves will reflect from the border of basin back to the direction of that tuning fork. And after a moment, the waves will disappear.
This demonstrates that when sound travels in a given medium, the waves that carry sound energy will strike the surface of another medium and bounce back in the other direction. This process is called as the reflection of sound.
The fraction of sound energy depends on the surface that reflects it. If the surface is rigid and smooth the reflected sound energy will become larger, while when the surface is soft and irregular it will become smaller. In fact, the reflection of sound is partially similar as the reflection of light. The angle of incidence is equal to the angle of reflection when sound reflects from smooth surfaces. On the other hand, if the surface is irregular the sound becomes garbled. There are plenty of examples in real life that utilize the reflection of sound. Some people like singing when they are taking shower for the wall of bathroom is smooth and hard. In contrast, in professional recording studio the walls always are made by absorbent material and rigid matter, to decrease the echo when the singer is recording. Also the amazing stereo of auditorium and concert hall relies on the balance of reverberation and absorption.
Furthermore, The principle of seabed acoustic detector is the utility of the reflection of sound. Scientists use the seabed acoustic detector to discover the geographical feature of submarine world. The detector sends out the sound energy in any direction and receives the reflected sound. Through analyzing the angle, length, power and the time gap between sending sound and receiving it, the detector can depict a digital topographical map of underwater world, which helps humans grope unexplored place with low risks.
Science is around us.