Links for Scientific Notation Videos:

http://www.youtube.com/watch?v=i6lfVUp5RW8&feature=relmfu (converting to and from scientific notation)

http://www.youtube.com/watch?v=nfTbTFJhbgo&feature=related   (multiplying and dividing with scientific notation)

http://www.youtube.com/watch?v=gF6ziWhY6ls&safe=active (adding and subtracting with scientific notation)

http://www.youtube.com/watch?v=PvT51M0ek5c&feature=related (mole)