First I'd start with the understanding that science fiction is literature that examines the human response to the effects of science. Then I'd recommend these diverse, newbie-friendly stories:
- Jurassic Park by Michael Crichton.
Pure fast paced adventure yet also an examination of how we can lose control when we allow technology to let us play God.
- Ender's Game by Orson Scott Card.
A big space and aliens story, but accessible through the perspective of a child.
- Frankenstein by Mary Shelley.
One of the first works of science fiction. It asks whether just because we could, does that mean we should while also asking what it means to be human.
- The Hitchhiker's Guide to the Galaxy by Douglas Adams.
Space, aliens, quantum physics - it's all there, but sweetened by hilarity.
- Brave New World by Aldous Huxley.
A fascinating look at the individual versus society in a futuristic setting where people are manufactured.