Manual iPad photography?

I will be teaching an introductory photography course to kids this summer. I was supposed to have access to old DSLRs, but now I don't. I could get an iPad for each student though.

Is there any kind of app that will allow the kids to simulate changing shutter speed, aperture, and ISO?

I'd like them to see how, for example, taking a photo at 1/30 is different than taking the same photo at 1/1000; how depth of field changes with aperture; how ISO affects exposure settings and image quality; etc. Is there a way to do this or simulate it effectively with an iPad app?