The suggestion of science magazines is a good one. I have found Scientific American more technical and less interesting these days than it used to be forty years ago. For a young person, I would recommend Science News over it–it has shorter and more exciting articles.
For biology, I think that Matt Ridley has written some fantastic, generally accessible books. I especially like Genome: The Autobiography of a Species in 23 Chapters, but his other books are quite interesting as well.
For mathematics (of the entertaining variety) I recommend Ian Stewart books and for logic, Raymond Smullyan.
In looking for books for a high school student, I’d go with recommendations that interested scientists make outside of their own field. I think I am too close to quantum physics to make good recommendations in that area, although John Gribbin’s books might be a good bet.
Some high school students really like the experience of working in a research lab, and some don’t. A student should not write off a scientific career just because he/she finds the type of work that high school students are allowed to do in a research lab pretty boring. (Often, that work actually is pretty boring.)