This is abstract about key iPad features and characteristics. Here you can learn few differences between iPhone and iPad phenomenon. :)

1. Split view – you can use this iPad-only element to display more than one view onscreen at a time, such as to present data in a master-detail or source list–style arrangement. The split view is a common organizational element in iPad applications because it helps flatten the information hierarchy.
2. Popover – you can use this iPad-only view to temporarily display additional information, controls, or choices related to content in the main view. The main benefit of the popover is that it can contain information or choices that don’t need to be in the main interface all the time.
3. Results list button – you can use this system-provided button to reveal search results from a search bar.
4. Modal views have new presentation styles – you can use styles such as full screen, partial screen, and form to present a modal interface that’s more closely tailored to your application’s user experience and visual design.
5. Toolbars can be in additional locations – you can place a toolbar at the top or the bottom of a screen. You can also use a toolbar inside a split view or a popover.
6. The edit menu can display custom items – you can supply menu items to augment or replace the standard Cut, Copy, Paste, Select, and Select All commands.
7. The keyboard view can be customized – you can replace the system-provided keyboard view with a custom view that contains custom buttons.
8. The keyboard view can include custom input accessories – you can supply auxiliary keyboard controls that users can tap to input application-defined content.
9. Custom text views can support text in multiple styles and offer advanced editing features – You can offer word-processing capabilities and support spell checking and autocompletion for text entry.

iPhone Applications – iPhone applications are optimized to run on iPhone and iPod touch. These applications run on iPad in their original resolution or can be optionally set to be pixel- doubled to accommodate for the larger display.

iPad Applications – iPhone SDK 3.2 supports the development of iPad applications that are optimized to take advantage of iPad features, but run only on iPad.

Universal Applications – iPhone SDK 3.2 supports the development of Universal applications. A Universal app is optimized to run on all iPhone OS devices—itʼs essentially an iPhone app and an iPad app built as a single binary.

Cheers!