If a book or a TV show is about science, but it's made so it's easy for everyone to understand, then it is popular science. It has popular in its name because it's made for the whole population, not just for scientists. Nature documentaries (nature shows) are examples of popular science.
Popular science is also not the same as Science journalism. Science journalism is what journalists write to report the newest theories and discoveries made in science, but popular science is not always about what is newest.
Popular science and scientific literature [change]
When scientists write about their work, first they write books and periodicals meant for the same kind of scientists to read-- scientific literature. The purpose of popular science is to show scientific literature in a way that different types of scientists, and people who are not scientists, will easily understand. When people take an idea from scientific literature and change it into popular science, important things about that idea are often left out or added in.
Scientific literature is made to seem like the ideas in it are not very new, and that the writer is not sure the idea is true. That way, other scientists will agree with the idea more. But popular science is made to be like other media, so many people will enjoy it. In popular science, ideas are made to sound like they are new, and like scientists all agree with the ideas. If scientific literature and popular science are compared, there is often a big difference. Even if most people agree about the subject, there is still a difference.
Some popular science is made by people who do not understand the subject well. Some is made by people who have a strong bias. Some is part science and part pseudoscience. It can be hard for someone who is not an expert to tell which works of popular science are misleading.
- Jeanne Fahnestock, "Accommodating Science: The Rhetorical Life of Scientific Facts" in The Literature of Science, pp 17-36