The aim of this project to further develop your understanding of forensics in a mobile capacity
The project is much geared towards self-learning, therefore I am happy to discuss any idea(s) you may have regarding the type of research you wish to undertake.

Suggestion 1

Snapchat is a popular mobile photo messaging app developed by Stanford University students. The app facilitates users to send and receive videos and photos to other users of the app on their friends list.

Users set a time limit for how long recipients can view their Snaps (as of April 2014, the range is from One to Ten seconds). Subsequently the message "disappears" from the recipient's device and is "deleted" from Snapchat servers.
A goal for this project could be to forensically recover a picture message and/or a video message that has vanished from plain view. The process of recovery should stand up to cross examination.

Suggestion 2

Siri for Apple's iOS functions as a voice-activated personal assistant. After it was acquired by Apple, Siri was first supported on the iPhone 4S and is currently used on most iOS devices including the iPhone 5, iPad 3, iPad Mini, and fifth-generation iPod Touch. Siri can perform a variety of functions and is often used as a hands-free method to send commands to the device, such as making calls or transcribing and sending text messages.

In order to interpret and act on voice commands, the program must at some point record the user and perform voice recognition. The request must also be converted into some form of text for web services to be able to answer it. These facts along with Apple's patent detailing the basic processes of Siri
leads to the belief that Siri must record and store the user's requests somewhere on the device for future reference. Questions that can be answered

1. The exact method used by Siri to handle requests.
2. What information Siri stores on the device, and where.
3. If any information can be extracted and parsed into a form useable by a forensic examiner