NSTA.org posts a free article from each of their journals every month. This month you can get:
CSI for Trees from Science & Children (Elementary)
No More Leaks from Science Scope (Middle School)
Using Issues-Based Science in the Classroom from The Science Teacher (High School)
I highly recommend joining NSTA (lots of great resources)- you receive one of the journals with your membership and you also get electronic access to all of the journals.
Applications for Science Teachers: Regardless of your grade level and membership status you will find many practical resources to support your science teaching.
Science for All 