Choosing between potential studentships/projects in the same department?

I have a conundrum at the moment in that I intend to apply for teaching/demonstrating PhD studentship...the department is looking to recruit 4 people this year and has listed 4 available projects. One of these is what initially attracted me to look into applying, but in the process I've also discovered an interest in another of the projects...so the question now is how to decide between them?

The idea of applying to both did cross my mind but did not seem so wise, as it wouldn't exactly give the message of being committed to either project...and the interviews etc are on the same date.

I've been trying to weigh up factors relating to how each matches my interests and how likely it might be that I could be accepted...but still reached no conclusion - any advice?

Can you ask someone trusted e.g. uni lecturer you already know etc how this would be looked upon? Are the projects related? Usually people have a broader research interest and might be suitable for numerous different projects. Can you find out via the uni if people have applied to multiple studentships before and how it is viewed? I'd suggest asking that question of the administration staff for the department maybe.

Good luck.

I think this is excellent advice. I applied for three projects all within one department because I thought they were all interesting. They had a common, underlying theme. They looked upon this favourably, after all, they'd written all the briefs so they thought they were all good projects too. Of course, this may not always be the case and I was asked at interview to indicate an order of preference. Good luck with your decision.

Thanks for your replies. I'm still not 100% sure about this but am leaning more towards one than the other now...
I'm no longer considering applying to both simply because of time restrictions (the deadline seems to have sneaked up on me for this one!) and the 'go-to' person I would normally speak with on this kind of thing is away. As always in my life, I'm concerned about making a 'wrong' decision...but of course a decision is better than no decision (and I guess it isn't a committed decision unless they actually offered me a place)