I recently came across a science series for grades 3-6 that will intrigue even the most reluctant readers! The series is:
Doyle & Fossey Science Detectives.
There are five books currently out and they all revolve around two main characters, fifth-grade sleuths- Drake Doyle and Nell Fossey. The two sleuths solve mysteries involving scientific principles. What is really cool is at the end of the book there are instructions for the experiments that were used to solve the mysteries.
I definitely think this series could be recommended to kids who seem to struggle to get interested in books!
Here are the titles in order:
The Case of Gosping Garbage
Mossy Lake Monster