Here are some ideas:
-Talk about good study or school habits
-Study techniques
-Fun facts (possibly about space... kids always like cool facts about planets)
-What they could do to be more economically friendly
-At home science experiments
-Volunteer opportunities (like if there is a teacher at school that wants help with grading papers, packing up class rooms, etc.)
-Dangers of technology or social media
-New inventions
-Life story of inspirational people (Racheal Joy Scott is an amazing one to write about)
-Science behind eating healthy/exercising and what it does to the brain, body, mood, etc.
-Ways to cope with anxiety/stress
-How to deal with puberty and mood swings
-How to help friends with depression (I don't know if this one is <em>as </em>applicable to this age group but it could be interesting)
-Science behind kindness (like the psychology behind it. What people who are kind tend to feel, what are the mental/physical benefits of being kind, etc. I did a research paper on this and it was actually really interesting)
-Since summer is coming up you can write about activities the kids can do when board (crafts, games, etc)
-Benefits of being outside (might convince some of them to not stay inside as much)
Hope this helped! Let me know if you want more ideas!