Can I describe in my own word few experiments from some academic papers to write a popular science book?

In general, copyright protects words, sounds, images, and similar artifacts. Copyright does not, however, protect ideas or knowledge. The use of ideas and knowledge can be protected by a patent. No intellectual property right, however, can be used to prevent a person from describing a published piece of information in their own words.

In your case, it sounds as though you are taking what you have learned by reading about this scientific work and presenting it with your own original words and images. As such, I think that you have nothing to fear, as long as you are certain to give appropriate references and credit to the original authors whose work you are describing. In a popular science publication, such citations might be more informal than in a peer-reviewed scientific paper, but as long as they are clear to the reader, what you describe doing appears to be entirely ethical and appropriate.

In addition to what Jakebeal said in his answer, what you are worried about is common practice in review articles, science journalism, textbooks, and of course other popular-science books. Producing either of these would be extremely tedious if there were a copyright issue. Also, if this were an issue, I should have encountered it in my experience with the former two.