To mirror an iPad display in the classroom, you need an iPad 2 or later, iOS 5, and either an Apple TV or MacBook with the Reflection app installed. The Reflection app costs $14.99 and allows you to wirelessly display your iPad screen on your Mac. To start mirroring, open the app menu on the iPad, select AirPlay, choose your Mac, and toggle the mirroring switch to on. This will display the iPad screen through your Mac to a projector.