Math in Google Docs with Built-in "Equation Editor"

Google Docs has an easy to use equation editor that offers a convenient way of inserting mathematical notation and maths symbols into a document

This blog post gives directions on accessing and using the Equation Editor:
http://paulhami.edublogs.org/2012/02/11/math-in-google-docs-with-built-in-equation-editor/

Internet 4 Classrooms

http://www.internet4classrooms.com/grade_level_help.htm

Physics in Real Life

A fantastic resource provided by PBS to help kids understand Physics in real life (or at least in the circus)
http://www.pbs.org/opb/circus/classroom/circus-physics/

Bookwink

http://bookwink.com/index.html

Below is from their site: 
Bookwink's mission is to inspire kids to read. Through podcasting and web video, we hope to connect kids in Grades 3 through 8 with books that will make them excited about reading. The videos are approximately 3 minutes long and are updated monthly. Each video booktalk is about a different topic, and additional read-alikes can be found on the Bookwink website. You can look for books by subject, grade level, author or title. We are constantly updating the book lists with our newest favorite books.  

Tip: To view video full screen, click the arrows in the bottom right-hand corner of the video.

Word Hippo

http://www.wordhippo.com/

Enter a word and it will find its definition, similar words, opposite words or words which rhyme with that word.