juice baR http://scienceview.berkeley.edu/showcase/flash/juicebar.html
zoom lab http://pbskids.org/zoom/games/kitchenchemistry/virtual-start.html
pH factor http://www.proteacher.com/cgi-bin/outsidesite.cgi?id=5268&external=http://www.miamisci.org/ph/guide.html&original=http://www.proteacher.com/110052.shtml&title=The%20pH%20Factor
ph scale http://www.watercampws.uiuc.edu/waterclear/labs/lessons/pH_teacher_guide.pdf