F1 and F2 keys control screen brightness, making the screen less or more bright. F3 shows all open windows using Expose view. F4 displays the Dashboard with tools like a calculator and weather app. F5 and F6 currently have no assigned functions. F7, F8, and F9 act as playback controls for rewinding, playing/pausing, and fast-forwarding media in apps like iTunes and QuickTime. F10 mutes sound, while F11 and F12 lower and raise volume respectively.