Cola Soda Rots Teeth!

Can the acid in drinks really weaken your teeth?




This science fair project was performed to find out if carbonated soft drinks can really cause the erosion of tooth enamel. Testing was done by immersing teeth in cola/soft drinks for a few days

This information can also serve as a warning sign  to parents whose children are asking for a pop.

“The bottom line is that the acidity in all soft drinks is enough to damage your teeth and should be avoided,”


The purpose of our project is to see what sports drinks/cola  do to teeth and the extend of damage they do to teeth

This experiment will  alsohelp students determine the effects of sugary drinks on teeth.


Sports drinks/Soda  have a negative effect on teeth.

Many children drink sports drinks/soda

The Teeth that are submersed in Coca-Cola and Hi-C will show significant changes in color, wear, and

weight compared with the ones submersed in water.

Immersing teeth in soft drinks will cause tooth erosion and the teeth will lose some of their weight.


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.


5 Days or 5 weeks


1  cup of water
1 cup of Coke
1 cup of Diet coke
1 cup  of Mountain Dew
1 cup  of Diet Mountain Dew
1 cup  ofroot beer
1 cup of orange juice
pH test strips
Clear cups or glasses/Beakers ideally with lids.
Dental  Tweezers
Real Human Teeth(of identical size and weight)
Magnifying Glass
Digital Weighing Scale
Survey sheets
Vinyl stickers/Labels for marking beakers
Latex gloves


  1. Measure out 1 cup of each type of drink and pour each into its own cup.
  2. Make sure to include one cup with water (This will be your “control” that you will compare the other liquids to.)
  3. Dip one pH test strip into each drink and lay on a flat, dry surface. Use the key provided with your pH strip package to interpret the pH result for each drink and record it.
  4. Wash and clean all the 6 real human  teeth specimens. Dry them, check their weights on the digital weighing scale and their color and texture and record the readings.
  5. Take a photo of the cup  as a proof of how teeth  were at the beginning and after the experiment.
  6. Using dental tweezers pick up each tooth sample  and put one  tooth into each cup. Wear gloves while handling teeth. Let them sit at room temperature for 5 days or 5 weeks. Keep the cups undisturbed.
  7. After 5 days or 5 weeks  take out the tooth from each cup and make observations about its color, texture and weight. Compare each experimental  teeth to the “control” teeth  that was just soaked in water.
  8. Weigh the teeth samples  again to see if the weight  had changed after  soaking in the drinks.
  9. Try to scratch the enamel off of each tooth using dental scaler. Take another photo and  record your results and compare the effects of the 6 drinks.
  10. Subtract ending measurements by starting measurements . Put results into a graph or table.


Beginning the Experiment

What is pH?

Scientists use something called a pH scale to measure how acidic or basic a liquid is. pH stands for power of hydrogen, which is a measurement of the hydrogen ion concentration in a solution. The total pH scale ranges from 0 to 14, with 7 considered to be neutral. A pH less than 7 is said to be acidic and the closer the pH is to 0 the more acidic it is. Solutions with a pH greater than 7 are basic, or alkaline, and the closer the pH is to 14 the more basic it is.

Which liquid in this experiment do you expect to be the most acidic?

This depends on the liquids chosen for the experiment. Remember, the closer a liquid’s pH is to 0, the more acidic it is!

During the Experiment

How does the color of the pH strip indicator change when I test liquids of different acidity levels?

This depends on the type of pH test strip you use. The key provided with your pH test strips will tell you what colors to expect for different levels of acidity.

Why is it important to have a “control” tooth soaked in water?

Comparing the teeth  soaked in the different liquids to a “control” tooth  soaked in water gives you a more accurate baseline. This way you can figure out whether what you are observing comes from the fact that the tooth  was soaked in a liquid or whether it is actually something about the liquid that causes what you are seeing.

After the Experiment

Which liquid weakened the tooth enamel the most?

Depends on the liquids used. Generally, the more acidic liquid should cause the most weakening of the tooth enamel.

Which liquid had the least effect on the enamel?

Depends on the experiment.

How it Works

Constant exposure to acidic drinks strips the enamel (the hard, protective layer of a tooth.) When tooth enamel is exposed to acidic beverages, it softens and loses some of its mineral content.

Saliva will help neutralize the acid, restore the mouth’s natural pH balance, and slowly harden the tooth enamel again. However, because the tooth’s recovery process is slow, if the acid exposure happens frequently, the tooth enamel does not have the chance to repair. This can cause tooth sensitivity and lead to the need for dental treatment to protect the tooth and the dentin underneath.


Independent Variable:
Type of Drink

Dependent Variable:
Tooth Decay/Damage

Control Variable:
Teeth, Plastic Cups, Amount of Drink

Control Group:

Experimental Group:
Tooth in Soda/Juice


. The lower-pH drinks, like Pop and lemonade, are the worst offenders

.  Anyone can have a Coke once in a while without harm – it’s what you drink habitually that matters.

Exposure time.
Sipping acidic drinks slowly (or, even worse, swishing it about in your mouth before swallowing) gives it more time to attack your tooth enamel. To minimize the effect, drink it quickly and try to keep it off your teeth!



An acid is a chemical species that donates hydrogen ions. The higher the concentration of hydrogen ions produced by an acid, the higher its acidity and the lower the pH of the solution.


A disorder resulting in the breakdown and dissolving of tooth enamel.


Enamel is the hardest substance in your whole body, and it covers and protects your teeth.

pH Level

pH stands for power of hydrogen, which is a measurement of the hydrogen ion concentration in the body. The total pH scale ranges from 0 to 14, with 7 considered to be neutral. A pH less than 7 is said to be acidic and solutions with a pH greater than 7 are basic or alkaline

Dental erosion – the loss of tooth enamel caused by acid attack. It affects the whole surface of the tooth. Progressive loss of enamel leads to shrinking and wearing of the tooth and crumbling at the biting edges. Over time, the dentin is exposed and the teeth become very sensitive.

pH – in this case, a measure of how acid a liquid is. The lower the pH, the more acid the liquid is. Neutral is 7.

Analytical balance – a balance that can weigh things accurately to 0.0001g



  1. Why do you think the teeth changed color, texture, and weight, if they did?
  2. What can you do to prevent this effect?
  3. What do you think are some of the individual long-term effects of drinking each of these liquids?


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.


What did we learn from our experiment?

We learned that sports drinks have a negative effect on teeth. A lot of kids drink sports drinks not knowing what it is doing to their teeth.

How close were our hypotheses and conclusions?

Our hypotheses and conclusions matched. We guessed that sports drinks did have a negative effect on teeth and that lots of kids drank sports drinks. We were right.

What was the most interesting part of our project?

It was going to the lab and weighing the teeth on the Mettler analytical balance.


It is observed that all the teeth immersed in the soft drinks lost some weight daily

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