Are you wanting to work for hire? From my perspective, you should ask yourself these questions:
Can you meet deadlines? Your deadline is critical, and you may only have a month or so to get the job done. The packager needs you to meet your deadline because they have to put your words together with the visuals in the design. They are likely putting together several titles in a series at once and it all has to come together by the deadline they have with the publisher. You cannot hold up the process.
Do you like doing research? Nonfiction titles will most definitely involve research. Know your way around a library? Not scared away by academic texts? Can you tell a reliable source from a not-so-reliable one? Excellent! Are you able to distill a big concept into an age appropriate package? You need to be aware of expectations in sentence length, the use of contractions or not, and vocabulary. Look at the book Children’s Writer’s Word Book for a solid overview. Also be aware of what concepts kids are taught at different grades so you’ll know which ideas/facts should be known and which are not. Look up your local provincial or state board of education and you’ll probably find the curriculum expectations all laid out.
Can you write quickly and clearly? There is little room for creative license in this type of writing. Plain and direct language is needed. Example: In my creative writing I might describe a con trail as “jets chalking the sky.” In educational work for hire it’s just a con trail with the definition to follow or written in a glossary.
Are you a team player? This is the publisher’s and/or the packager’s vision for a final product. You yourself might approach the whole topic in a differenet way, but that’s not what you were hired to do. You have to carry out someone else’s direction. You need to understand that a topic expert, an educational expert, and someone at the publisher as well as your editor at the packaging company are all going to comment on and have input into your work. All these views need to be incorporated into the final text.
If you answer yes to all those questions then give it a try. With a background in a particular science or other disipline, you might start there by looking for publishers who specialize in science or who produce books on history. Try writing some nonfiction for magazines to build up your writing resume. When you’re ready for work for hire book work, SCBWI maintains a list of educational pubilshers and a list of packagers for members. You can also find this type of info in Children's Writer's and Illustrator's Market. Good luck!