3.Phonetics and Phonology: Introduction

Today, I watched a short video about phonetics and phonology, which made me better understand the sound system of English. Previously I was a bit confused about these two terminologies, but this video refreshed my memory about what I had learnt sometime before. 
Phonetics is smaller than phonology. The unit of phonetics is called the phone which is not the same as the phone we use to call people. However, phonology is more systematic and its unit is named phoneme.  Also, in phonectics it usually looks like /r/, while in phonology it is in the bracket - [r].

Phonetics is a scientific description of what speech sounds exist in a language. It represents how they are produced and perceived and what acoustic properties they have. Thus, it can be put in the class of natural sciences. Phonetics essentially seeks to trace the processes physiologically involved in sound production. It describes the ways the sounds are produced and the points at which they are articulated. 

Phonology is concerned with the regularities that govern the phonetic realisations of sounds in words of a language. It looks at and tries to establish a system of sound distinctions relevant to a particular language. It then seeks to determine how the elements of this abstract system behave in actual speech. Phonology actually delineates the functioning of sounds in particular contexts. 

From the above, it is obvious that phonology is not phonetics, neither is phonetics phonology. They are however both subject to descriptive details if proper instrument of analysis is applied. The question then is: what is the difference? From the definitions above, the difference should be somewhat obvious. We have said that phonetics describes the physical realisation of sounds. It studies the physiological processes involved in sound production. Phonology on the other hand looks at the behavioural patterns of sounds in actual speech, their realisations in different environments, whatsoever these may be. 

https://youtu.be/80d2CEeMyQQ