OSX and Applications on separate drives?

I was given a late present, a small 30 GB SSD drive that will fit in my Mac (replacing the DVD drive which never gets used). Is it possible to use two drives on OSX, maybe the OS, all of my photos, Photoshop and Lightroom (since what I use it for the most is editing)? Google isn’t really giving me the information on what needs to be on what drive or if I need to do a clean install. Can there be two application folders?

There’s nothing stopping you from installing programs to a folder other than the default Applications one.