functions of the keyboard ( resubmission )

PIANO
Is played using a keyboard,made of usually white and black keys, is made of wood, to make it sound, when you press a key ,an small hammer hits a string inside of the piano making in resonate , and once this key is released the string will stop sounding.There are some pedals that will extend the sound or mute the sound depending on the pedal used. This little hammer touches the string as hard as you hit the key , depending on the acceleration you want to achieve.
PIPE ORGAN
A pipe organ has works nearly the same way as a Piano, the difference is that the piano creates a sound by using strings, the Pipe Organ releases air that travels pressurised into pipes, this pipes depending on the size or set up it will change the pitch,timbre, and volume.
By pressing a key, it will press also a valve the the air is kept,then it sends it the air compressed into the mouth of the the pipe, as the air is compressed it makes it sound depending on the ratio ( size ) of the pipes.
HARPSICHORD
The harpsichord works similar to a keyboard, as the sound is made by the strings inside the piano , same system, when a key is pressed it acts on the strings , but this time it doesn't hit them,it plugs the strings.
By pressing the key , there is a mechanism inside that makes the string sound, as soon as a string is pressed a small strip of wood will lift , a piece of wood that holds a plectrum.When the plectrum goes up it touches the string, when it is released ,the strip of wood moves to the side slightly so it won't touch the string a again on it's way back.
ELECTRIC KEYBOARD ( SYNTHESIZER )
The electric keyboard has the same keys and same system as the other keyboards, but it doesn't have anything physical being used, apart from electricity as the name says so.Depending on the brand or model of this keyboard the sound may vary, this is to do with the purpose it was made for, either for certain genre,ambience or region.
When a key is pressed is touches a certain button , this button will send digital information ( MIDI ) towards different components inside the keyboard, giving the information needed , like the velocity, volume, and key played then finally travelling into the output.

ELECTRIC KEYBOARD ( SAMPLER )
This kind of synthesizer instead of producing the sound, the sounds are saved into a memory, depending on the type of sampler, the way of operating it can vary, the sampler can have the sounds saved into an internal/external memory, then it gets triggered by pressing any key of buttons that can produce MIDI data.
So depending on the storage memory,many many sounds can be saved and used with a sampler, it can easily imitate nature sounds,and other intruments.