How come sound isn't measured in Joules if it is a form of energy?
http://en.wikipedia.org/wiki/Sound_pressureSound pressure level (SPL) or sound level is a logarithmic measure of the effective sound pressure of a sound relative to a reference value. It is measured in decibels (dB) above a standard reference level. The commonly used "zero" reference sound pressure in air is 20 µPa RMS, which is usually considered the threshold of human hearing (at 1 kHz).
The formula for predicting the loudness of an impact in deciBels is: Loudness (dB) = 20 * log (Pressure (P) / Reference pressure (Pref))
Loudness is measured in deciBels (dB), which is a logarithmic unit.
The reference pressure used in the formula is 20 microPascals (µPa), which is the threshold of human hearing.
The formula does not explicitly take into account the size and material of the impact object. However, the pressure (P) in the formula can be affected by these factors, as a larger or denser object may create a higher pressure upon impact.
No, the formula may not be able to accurately predict the loudness of all impacts. It is based on certain assumptions and may not account for all variables that can affect the loudness of an impact, such as distance from the impact or the surrounding environment.