Apple MacBook Air (Late 2008), (Mid 2009) - Manual (Page 35)

Chapter 2 Life with Your MacBook Air 35
 Four-finger swiping works in the Finder and all applications. Swiping four fingers to
the left or right activates Application Switcher so you can cycle through open
applications. Swiping four fingers up or down causes Exposé to show the desktop or
display all open windows.
Running Your MacBook Air on Battery Power
When the 45W MagSafe Power Adapter isn’t connected, your MacBook Air draws
power from its built-in rechargeable battery. The length of time that you can run your
MacBook Air varies, depending on the applications you use and the external devices
connected to your MacBook Air. Turning off features such as AirPort Extreme or
Bluetooth ® wireless technology can help conserve battery charge.
If the battery runs low while you are working, attach the power adapter that came with
your MacBook Air and let the battery recharge. When the power adapter is connected,
the battery recharges whether the computer is on, off, or in sleep. The battery
recharges more quickly, however, when the computer is off or in sleep.