NASA for middle-school students http://www.nasa.gov/audience/forstudents/5-8/features/index.html
National Geographic for Kids http://www.nationalgeographic.com/kids/
Science News for Kids Articles from this site can be used for current science, but you must print a copy to turn in. http://www.sciencenewsforkids.org/
Astronomy Magazine Articles from this site can be used for current science, but you must print a copy to turn in. Articles can be found under NEWS on this site. http://www.astronomy.com
Sky & Telescope Magazine Articles from this site can be used for current science, but you must print a copy to turn in. Articles can be found under NEWS on this site. http://www.skyandtelescope.com
Tweentribune Articles from this site under science can be used for current science, but you must print a copy to turn in. Articles can be found under science on the right side of the page. http://tweentribune.com/