Good for occasional writing assignments
Community Review for Science News for Students
Science News for Kids has a lot of articles in many different fields. You can search by category and age. There are a collection of archives that aren't exactly "news" but are still well-written articles that you can read with students or they can read independently. There are many interesting topics that keep kids interest and are written on a level they can understand. They will usually have a few good vocabulary words you can highlight and discuss.
How I Use It
I try to find interesting articles that may be relevant to recent events or recent topics we have covered or sometimes to introduce topics. We read the articles out loud (in a general setting), taking turns reading a paragraph or two. Then students would summarize and write their reaction to the article. This would satisfy my school's requirement to have a weekly writing assignment.