I am going to sound a little pessimistic right now but we have been writing research papers in 5th grade lately. Now that the internet exists as a tool for doing research, I have noticed some kids (rather than taking notes) copying and pasting information directly into their word file for their essay or presentation. This isn't a new problem - plagerism was just as common when we use to use encylopedias, but there are new tools that help teachers check students work. Being a teacher means I need to find the free options. There are plenty of websites that will allow you enter the text of a paper and charge you $8 a paper (or more, or less.) Below are two that I have found to be accurate and free. I never want to assume "evil intent" on a student's part, but I do want them to learn at an early age that copying someone else's work is wrong and can be easily detected. Better to learn this in elementary school when the stakes are lower than when it is on your college entrance essay!
http://smallseotools.com/plagiarism-checker/
http://www.paperrater.com/plagiarism_checker
http://smallseotools.com/plagiarism-checker/
http://www.paperrater.com/plagiarism_checker