Magnetic Fields Can Control Heat and Sound.

摘要

Sound is carried by periodic vibrations of atoms in gases, liquids and solids. When we talk to each other, the vocal chords of the speaker vibrate, causing the air coming from his lungs to vibrate as well. This creates sound waves, which then propagate through the air until they hit a listener s eardrums and make them vibrate as well. From these vibrations, the listener can then reconstruct the speaker s words. Sound is affected by the surroundings in which it travels and by the frequency of the sound waves. We design musical instruments to manipulate the sound waves they produce. Further, we know that there are sound waves that are outside the range of human hearing, such as those produced by a dog whistle. As physicists have researched sound both inside and outside the range of human hearing, interesting properties have been discovered.