http://www.learner.org/courses/envsci/
http://teacherstryscience.org/kids
http://www.nature.com/scitable
http://ed.ted.com/periodic-videos
http://static.itnsource.com/compilations/science+techvideotimeline
I have been getting ready for next year and I found a great website for history! It is intended for secondary education, but I think that I will adapt it for my son who is in middle school.
https://www.bighistoryproject.com/home
It has a sign up for the teacher and the student. I really think that we are going to love this!