hi, i'm pretty new at this, but all that looks like is a simplified photocell, instead of connecting a digital input, it looks like you can connect 5v to it one side, and connect ground to the other side, and use the middle to connect it to an analog input to give you numerical data ( which is really good )
but i really cant be sure unless i have it with me, and i try to connect it. ask your teacher, or whoever knows alot of stuff what the wires are, ask if one is power, one is ground, and one is data
hope this helped 
edit:
just saw the pic again, and i'm pretty sure that what i explained above is what it is.
so yes, this can be connected to the arduino, good luck!