Polymers, whether natural or artificial, are big molecules made by linking up smaller repeating chemical units. The most common âbackbonesâ for polymers are chains of carbon or silicon, each of which can bond to four other atoms. Polymers, whether natural or artificial, are big molecules made by linking up smaller repeating chemical units.
Details About Pitch. Although for most practical purposes, the pitch of a sound can be said to be simply a measure of its frequency, there are circumstances in which a constant frequency sound can be perceived to be changing in pitch.
The catch is that there are several decibel scales. Thus, in order to be meaningful, your audiologist indicates which decibel scale she used. The two most commonly used scales are the SPL (Sound Pressure Level) and the HL (Hearing Level) scales. Sound meters are calibrated in dB SPL. This makes total sense because the condenser microphones used in sound meters are sensitive to changes in sound pressure in the air, just as our ears are. In contrast, audiometers are calibrated in dB HL, not in dB SPL like you would think would be done.