PaperRater is a great site for Middles/High School students who want to improve their writing. This site checks student's writing by checking: grammar, spelling, and for plagiarism. Plus, it's very easy to use just copy/paste text in and click get report. This really should help students create more original pieces of work.
Give PaperRater a try by clicking here.
A special thank you to Richard Byrne and his excellent blog for finding this wonderful site.