Here’s a welcome resource for your budding 3D classroom: Phogy, a free 3D parallax camera.
This app (produced by Vivoti) runs on the Android platform (download here) or the iPhone platform (download there). Short instructions are available on the app, but the English isn’t quite correct, so it may take some re-reading to get started. Nevertheless, a great tool for the classroom. And the price is right.
Special note: The Apple version requires iOS 7.0 or later and is compatible with iPhone, iPad, and iPod touch. This app is optimized for the iPhone 5.