Thursday, July 12, 2012

Physics Concepts For Sound & Vibrating Air

Sound is made of waves that travel through the air, varying in wavelength, amplitude and frequency, and reflecting off material objects. Air in different areas will affect sound waves in different ways due to temperature, air density and humidity. The air does not vibrate itself, but simply carries the moving sound wave.


Parts of a Sound Wave


The wavelength is the distance from the peak of a wave to the peak of the next, while the frequency is the amount of waves that occur at one spot in a second. The amplitude of a sound wave is the level of energy contained therein. The compression is the amount of energy in the top part of the sound wave, while the rarefactions exist in the downward parts of the wave.


Air Changing Sound


Air temperature inversion affects the speed of sound. This phenomenon occurs "when the temperature is coolest right next to the ground and warmer" as height increases, according to Kettering University. When temperature increases higher in the air, speed of sound also increases. Different mediums will affect sound, like air and water, so when sound waves transfer back and forth between these materials, the sound's volume, speed and pitch, as well as other elements, can change.


Range of Sound


The pitch of a sound wave is how high or low the wave sounds. High pitches have high frequencies, while low pitches result from low frequency waves. Louder waves have higher amplitudes and soft waves have smaller amplitudes. According to NASA, "the time interval between waves passing is called the period." Sound levels can be described with decibels, which explain how loud or soft a sound wave is.


Sound Reflection


Some objects are made to absorb sound waves, but most materials reflect at least some parts of sound waves. The reflection of sound waves results in either echos or reverberations. Reverb occurs often in both small rooms and large concert halls. Reverb is preferred over echos, which can eventually lead to the multiplication of sound waves in a space. Rough walls reverb sound much better than smooth walls. The diffraction of sound waves changes the direction of the waves.

Tags: sound waves, sound wave, affect sound, sound wave, speed sound, waves have