Is there an application that can see hand gestures to turn on the screen and scroll? While I am cooking with dirty and wet hands, I want to see the recipe on my smartphone without dirtying it.

How may I turn on the display and scroll without touching the phone?

Is there an application that can see hand gestures to turn on the screen and scroll?
There may not be an 'app for that' but you can do what I see in many Chinese take-out places - put some cling plastic wrap over the screen like they do with the keys of the cash-registers. OtterBox also makes cases with screen protectors. Cling wrap is far less expensive, though.