1) The Martian, by Andy Weir. If you haven't heard about this book, you probably will sometime this year. Matt Damon is starring in a movie adaptation, which is set to premiere on November 25 of this year. The film also stars Jessica Chastain and is directed by Ridley Scott. I can only hope that the film is as good as the book. I initially heard it as an audiobook (as performed by R.C. Bray) and loved both the material and Bray's interpretation of it — I immediately bought it as an e-book. It's the story of astronaut Mark Watney, who gets stranded on Mars after a manned mission goes awry. He's a sarcastic and resourceful soul and the story is a suspenseful (and informative) tale about his attempts to stay alive and get rescued. Most interesting to me — apart from the great characters, which Weir describes mostly through their dialogue — was the science woven throughout. I think that with the exception of the storm that strands him there — Weir commented at one point that he learned that a windstorm on Mars wouldn't likely cause the event that sets off the plot — Watney describes and works through scenarios that are based on science. For example, at one point, trying to conserve energy for a mission on a rover, he turns off the heat in the vehicle and quickly realizes that Mars won't have it: "Within an hour I was chattering and numb .... There's no way I could do a long trip like this. Turning the heater on, I drove straight back to the Hab. Once I got home, I sulked for a while. All my brilliant plans foiled by thermodynamics. Damn you, Entropy!" That's the kind of writing that I think would appeal to a kid in high school — real-world science in a hostile and thrilling setting. Of course, a well-plotted and well-written story is appealing period, but I think it's a good way to introduce or expand on concepts that high schoolers might be covering in their science classes. The Martian actually re-sparked an interest in physics for me and I've since tried to re-teach myself some basic mechanics courtesy of Physics for Dummies. Just a heads-up if you do plan to gift this to the reading teenager in your life: The Martian does occasionally feature some four-letter words, mostly courtesy of Mark (I'd probably curse a great deal too if I was trying to stay alive on a hostile planet "determined to kill me," to paraphrase Watney) and also the hilarious character of NASA's director of communications Annie Montrose. I actually think that some cursing would probably appeal to teenagers, but you know, heads-up in case that causes some concern. :)
2) What if? Serious Scientific Answers to Absurd Hypothetical Questions by Randall Munroe. The author of the great site xkcd.com, Munroe answers crazy hypothetical questions with well researched, thought out, wry, and science-based answers. He also peppers them with his stick-figure comics, which are pretty hilarious in and of themselves. What if? is a compendium of Munroe's online answers plus, as the flap to the hardcover says, 51% more new questions and answers! I love these — they're funny, entertaining, and informative. One of my favorites in the book is also a great peek at the elements of the period table. The question is: "What would happen if you made a periodic table out of cube-shaped bricks, where each brick was made of the corresponding element?" The answer is detailed and hilarious. To give you a taste, Munroe describes the last row as the "Transuranic (Evil) Elements" and details the attempt to put them on the hypothetical cube wall in the question as such: "Unfortunately for our project, the transuranic elements don't vanish quietly. They decay radioactively and most of them decay into things that also decay. A cube of any of the highest-numbered elements would decay within seconds, releasing a tremendous amount of energy. The result wouldn't be like a nuclear explosion — it would be a nuclear explosion. However, unlike a fission bomb it wouldn't be a chain reaction — just a reaction. It would all happen at once .... The fallout wouldn't be normal, everyday radioactive fallout (footnote: You know, the stuff we all shrug off) — it would be like a nuclear bomb that kept exploding."
Other questions are equally answered in detailed and others are just labeled, "Weird (And Worrying Questions From the What If? Inbox," like "What temperature would a chainsaw (or other cutting implement) need to be at to instantly cauterize any injuries inflicted with it?" ....
Stuff like that is why I think teenagers would probably like the reading material ... interesting and sometimes disturbing! :) Anyway, enjoy! (And let me know if you get a chance to check either of the above out.)