Science fiction is a genre that blends authors' imaginative creations with scientific ideas, theories, predictions, and conjectures. It's also a genre of literature that's been behind the scenes of many inventions we use today. In fact, some of these technological advancements weren't even invented until after they were first written down.
The lines around what qualifies as sci-fi get a bit blurry, and some of the technology described in older works can still be seen in modern life. For example, Edgar Allan Poe wrote stories that were loosely classified as science fiction, such as The Balloon Hoax of 1844. But if you look at some of the most popular sci-fi books and films, they are often filled with technological speculation that doesn't always seem to match up with what is actually happening in the world today.
Inventions that are based on scientific principles include the atom bomb and rocketships. These are called hard science fiction and are typically based on actual scientific facts and discoveries (Harris-Faine). Soft science fiction is more of an artistic and philosophical genre and often takes place in an imagined future, or dystopia, that offers a contrast to the current state of society. This type of sci-fi can offer a variety of social commentary, and depict themes such as resistance to totalitarian regimes or survival in a post-apocalyptic world (Harris-Faine).
Some famous examples of soft sci-fi are tablet computers, chess playing robots and speech recognition. For instance, Ray Bradbury's 1953 novel Fahrenheit 451 included a reference to earphones that looked like "little shells." In the book, people slip them into their ears and hear an electronic ocean of sound. This prediction was a precursor to the invention of Bluetooth earbuds, which were developed in 1992.