I enjoyed the demonstration by Pernell Williams regarding the dilution of
food coloring. I do want to point out that students should be determining if
the solutions are COLORLESS as opposed to CLEAR. These words have different
meaning (Windex is blue color but is clear - you can even read the label
through the back side of bottle). I am also curious why 5:1 diliutions were
used when a 10:1 dilution would be a great way to introduce the pH scale and
log scale. Comments?