Computer Mouse???

    
       Once upon a time, if you'd seen a mouse in your room you might have screamed and jumped up on the desk. Today, the mouse has jumped on your desk instead: it's the handy little pointer that makes your computer easy to use. The first mouse was made of wood and designed over four decades ago in 1961. Today, mice sell by the million and hardly a computer ships without one.
       A mouse is something you push along your desktop to make a cursor (pointing device) move on your screen. So what a mouse has to do is figure out how much you're moving your hand and in which direction. There are two main kinds of mice and they do this job in two different ways, either with a moving rubber ball or with LED optics.
                                     

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Mechanical:  

This is a type of computer mouse that has a rubber or metal ball on its underside and it can roll in every direction.  There are sensors within the mouse, which are mechanical, detect the direction in which the ball is moving and moves the pointer on the screen in the same direction.  A mouse pad should be used under the mouse to run on.

Optomechanical:  

This is the same as the mechanical mouse except that it uses optical sensors to the motion of the ball.  Your should use a mouse pad under the mouse to run on.

Optical:  

This type uses a laser for detecting the mouse's movement.  You don't need a 
mouse pad but you can use one made for optical mice.  Optical mice do not have any 
mechanical moving parts.  The optical mouse responds more quickly and precisely than the mechanical and optomechanical mice and now that they have been around awhile the price is pretty comparable.

Cordless mouse:  

These are not physically connected to the computer.  They rely on infrared or radio waves to communicate with the computer.  Cordless are more expensive than both the serial and bus mouse.  The nice thing is that there is no cord to constrain or get in your way.

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