Tooth decay starts as early as the toddler years, so even kindergarten and early-elementary students can absorb simple lessons and experiments on the subject. The elementary age group is likely familiar with soda, and can begin to understand the causal relationship between sugar and dental health. Use photos of both healthy and discolored teeth to illustrate how eating habits affect health and well-being while introducing the experiment.
For secondary students, the experiments can be an opportunity to incorporate critical thinking. For instance, as a preamble to the experiments, have the students examine soft-drink print ads and commercials through the years via Web searches. Ask them to summarize the messages in these ads, and compare that to the reality of the drinks’ effects on the teeth and health in general.
Tracking the relationship between tooth decay and drinks begins with the most direct correlation – an experiment using a tooth and a supply of carbonated soda. Elementary students, especially those in the tooth-losing years, can collect their shed teeth to contribute to the project. If real teeth are in short supply, substitute chicken bones or seashells. Immerse the teeth in a glass of carbonated soda; cola works well, because the added food coloring leaves telltale stains on the teeth. Observe the tooth over at least two months, replacing the beverage every week. Over time, the students should observe signs of obvious decay of tooth enamel. Bring in a camera to record “before, during and after” pictures of the affected teeth.
Experiments that incorporate different liquids give middle school students the opportunity to correlate information and draw conclusions. Give these students teeth or tooth substitutes to immerse in carbonated soda, high-acid drinks such as orange juice, water and, as a non-potable variable, battery acid. Using the same time frame as the elementary experiment – with the teeth immersed for at least two months – have the class summarize the rate of discoloration and breakdown of the teeth, comparing what liquid causes the most damage or the fastest reaction.
High school students are ready to explore the chemical properties of soft drinks and report on the long-term effect on tooth enamel by conducting their own immersion experiments and comparing the results to published studies, such as one from the Academy of General Dentistry, which concluded that non-colas, while less acidic than colas, cause more dental erosion. Another experiment for high school students involves comparing the reactions of two categories of teeth – fluoridated and non-fluoridated – in the same cola glass.