Mouse
Mouse is a unique input device used with computers. Mouse consists of a hand-held pointing device, designed to sit under one hand of the user and to detect movement relative to its two-dimensional supporting surface.
This device has a set of buttons and/or other devices such as scroll wheels on the body to send signals to the computer. Depending on the application program, the mouse buttons can be programmed. In general, the left most button is used to activate something. Clicking twice consecutively on the left button you can open an application. Further, for the purpose of dragging and dropping an icon, the left mouse button can be used. The right mouse button, open and allow choosing from secondary menus.
Mechanical and optical mice are common in use. An optical mouse uses a light-emitting diode and photodiodes to detect movement relative to the underlying surface. A mechanical mouse has perpendicular wheels housed inside the mouse's body detected motion of the ball.