Where are the SAT Reading materials used in the videos?

Hello - This is my first time using Khan to support my SAT Prep class.  Just wondering where I can find PDFs  of the examples that he uses in the videos.  For example, I like the science reading examples about the turtles who find their own way by sensing earth's magnetism.  I would like my student to annotate the text the way he does in the video.  Do these texts exist somewhere?  Thanks to anyone who answers!