In simple terms, Aqua is what a user experiences when he or she uses Mac OS X.  Aqua governs the appearance and behavior of Mac OS X.  Aqua is the intuitive, elegant, and gorgeous graphical user interface (GUI) that Mac users use to get things done in Mac OS X.

In Mac OS X the Desktop is the area of the screen where your work begins.  After you turn on and log into your Mac you are taken to the desktop.  When there are no open application windows you will see something similar to the following on Mac OS X Leopard.

After you run Setup Assistant the first time you boot your Mac and the Mac OS X Desktop is launched, you'll see a transparent strip of icons located at the bottom of the screen called the Dock.  Most people's first impression is generally positive as the icons are very elegant.

Your Dock Your Customizations
Apple starts you off with a pre-configured Dock.  For some users this is sufficient but if you want to take your Mac OS X experience to another level, customize the Dock.  No two customized Docks are identical.  The focus of this guide is the Dock Behavior and effects.

You can change the default Aqua look and feel something much less vibrant and colorful.  If the bright blues, and the red, green, and yellow window buttons are not your forte, you can change all those elements to gray.

Mac OS X is capable of presenting to the user various icons.  Icons play a vital role throughout the operating system, in application windows, and within applications (programs).  Icons are simply symbols or graphics used to represent an entity with a particular program, window, or option.

When you preform certain desktop actions Mac OS X will play a short sound that lasts only a fraction of a second.