| Complexity level: | 4 |
| Project cost ($): | 10 |
| Time required: | 1 hour for preparation, 5 days for observation |
| Material availability: | Very easily found |
| Safety concerns: | None |
Hypothesis
Immersing teeth in soft drinks will cause tooth erosion and the teeth will lose some of their weight.
Overview
Tooth erosion by soft drinks
Soft drinks are carbonated beverages that can be consumed at room temperature or after being chilled in a refrigerator. Some popular soft drinks are cola drinks, orange soda, sparkling soda, root beer and ice cream soda. Most of the soft drinks contain little or no alcohol and are popular among children and adults.
Soft drinks normally contain acids that can dissolve the enamel of teeth. The pH levels of the soft drinks that we consume are between 2.5 to 4.0. Any solution with a pH level below 5.0 is strong enough to cause erosion in our teeth. Even the natural juices found in fruits like lemons and oranges contain citric acid and ascorbic acid, which can eat away at our tooth enamel.
The most common offenders in soft drinks are phosphoric acid and citric acid. Although occasional drinking of soft drinks will not do much harm to our teeth and health, it is the habitual drinkers that have much to worry about. Sipping the drinks slowly will only prolong the exposure of the teeth to acid and will only cause more damage to one’s tooth enamel.
Scientific Terms
Materials
The materials required for this science fair project:
- 3 transparent bottles
- 1 bottle of Coca Cola
- 1 bottle of Sprite
- 1 bottle of root beer
- 1 digital weighing scale
- 3 teeth (of identical size and weight)
Procedure
1. For this science fair project, the independent variable is the brand of soda used to immerse the teeth. The dependent variable is the weight of the teeth. This is determined by checking the weight of the tooth using the digital weighing scale once a day. The constants (control variables) are the size of the bottles, the amount of soft drink in the bottles, the size of the teeth, the temperature of the environment (which will remain at room temperature) and the length of the experiment.
2. Fill the 1st bottle with the Coca-cola, the 2nd cup with Sprite, and the 3rd cup with the root beer.
3. Wash and clean the 3 teeth. Dry them. Then, check their weights on the digital weighing scale and record the readings in a table, as shown below.
4. Place a tooth inside each bottle. After the first day, remove the teeth from each bottle and check their weights. Record your readings in a table. Then, refill the bottles and replace the teeth. Repeat this process every day for the next 4 days.
Results
It is observed that all the teeth immersed in the soft drinks lost some weight daily. The tooth that was immersed in Coca Cola lost the most weight and the tooth that was immersed in root beer exhibited the least erosion.
| Soft drink | Weight of tooth (grams) | |||||
| Start | Day 1 | Day 2 | Day 3 | Day 4 | Day 5 | |
| Coke | 2.3 | 2.28 | 2.26 | 2.25 | 2.23 | 2.21 |
| Sprite | 2.32 | 2.31 | 2.3 | 2.28 | 2.27 | 2.26 |
| Root Beer | 2.35 | 2.35 | 2.34 | 2.33 | 2.33 | 2.32 |
The above results were then plotted onto a graph, as shown below.
Conclusion
The hypothesis that immersing teeth in soft drinks will cause tooth erosion and the teeth to lose some of their weight has been proven to be true.
Soft drinks are very popular among children, teenagers and adults. Other than tooth enamel erosion, soft drinks are also associated with obesity, low nutrition and diabetes. This is because most soft drinks contain high levels of sugar, including fructose and sucrose. The presence of caffeine in some soft drinks can also cause sleep disorders and anxiety.
Also consider
The science fair project can also be repeated to test the effects of soft drinks on other calcium-rich materials, by using pieces of chalk instead of teeth.
The experiment may also be modified to test the effects of fruit juice on tooth enamel, by using natural juices like lemon juice, orange juice or pineapple juice.
References
Acids in popular soda erode tooth enamel - http://www.livescience.com/health/070321_soda_teeth.html
Acid erosion - http://www.doonsouthdental.ca/InfoAndLinks/Erosion/Erosion.html
