A. 20 mL of water and 2 drops of yellow food coloring
B. 20 mL of water and 2 drops of brown food coloring
C. 20 mL of water
D. 20 mL of water and 5 drops of brown food coloring
E. 20 mL of water and 5 drops of yellow food coloring
2. Label the cups with their corresponding letter as listed above in bold.
Note: Test the solutions on paper before doing the experiment. Slight differences in food coloring may change the amounts needed to create an easy-to-see continuum of “stains.” See the Results Table for descriptions of what color each solution should be when applied to paper.
Discuss the following questions with the students. Which teeth are the most stained and
why? How could someone avoid staining
their teeth like this? If Ann only used tobacco for a short
time, why are her teeth yellow? Explain
to the students that Denisha’s teeth are the darkest and most stained from
smoking cigarettes and that not smoking is the best defense against discolored
teeth. Highlight that Ann’s teeth are
slightly yellow because any tobacco use, no matter how little, can yellow
teeth. Stains get worse over time, but
the stains begin to form right after the start of tobacco use.