Science Fair - Which Drink Stains the White of an Egg the Most?

Every year, the students of Lacey Township High School are required to complete a science fair project for their science class of the year. Sophomore year, I had STEM Chemistry with Mrs. York. The project includes four things: a free display board, a research paper, a journal, and a presentation explaining the experiment. My experiment was based off of the decay of enamel on teeth due to different drinks over the course of a few days. The drinks used were tea, coffee, and soda and the data was collected over the course of seven days. The following is a quick summary of the project.

Abstract

The first step to finding the solution to this question is to conduct research into the topic. Multiple surveys with professional dentists have been done on the subject of drinks that stain and discolor teeth. Many people found that coffee was the drink to most likely stain the enamel on teeth since it contain caffeine and a lot of other harmful sugars. The harmful sugars then build up and cause discoloration of the off-white color of teeth. I wrote a research paper titled The Cause of Tooth Decay and Discoloration on this topic. It gave me insight into how teeth start to lose their original color and what speeds up the process.

The next step is to formulate an experiment to this question. I was able to create a way to observe how teeth would be able to react to different drinks without using real human teeth. I simulated teeth using egg shells since they contain the same off-white color. Before putting them into the liquids, I had to hollow them out since they would rot over a long amount of time. I hollowed out the eggs by using a pushpin to make holes on each side of the egg shell. I then had to blow out the insides of egg, only after breaking up the yolk inside of the egg, onto a plate. This would hollow them out and leave me with the shell. I then had to gather up the different drinks I would use for the experiment. I had to go to the store down the street to buy a bottle of soda to use, since we didn’t have anything available at my house. I then had to use the Keurig coffee maker to make tea and coffee. I then poured these three liquids into three different tupperware containers. It was at this time that I realized I had no control, or original egg, I could compare the others too. I then had to tweak my materials list and procedure to account for a fourth egg and hollowed out a fourth. I placed the fourth shell into a small, empty container and kept it in the same box as the other three containers.

Originally, I planned to only carry out observations for three days, but that turned out to not be enough data since the color of the eggs barely changed within the first few days. I wanted to see how dark the eggs could become, so I upped the observation time to a week. This gave me the results I needed. During the observation period, I had to make sure to observe the shells around the same time everyday in order to get consistent results. Even when I had no time to write about the data for that day, I still removed the eggs and took a picture to put into the journal. I then wrote about the picture the next time I had time. This ensured that all of the data was consistent. Near the beginning of the observation period, I had to change locations. I packed up all of the containers in a box and brought the bow with me on a car ride, trying to ensure that none of the egg shells cracked. I then continued everything that needed to be done for the few days I was away from home. I did not let time constraints or location changes prevent me from gathering my data.

The results were consistent and the eggs did exactly what was expected. All three of the eggs within liquids darkened in color. The tea shell was the lightest at an orange-brown color. The coffee shell was the second darkest at a solid, medium brown color. The soda shell was the darkest at a black-brown color. The only thing that was off was that coffee did not discolor the shell the most, as I had hypothesized. My hypothesis was not supported by the findings, but this sprouted a whole new range of questions. I based my hypothesis on what professional dentists had said; surely, they could not be wrong. A survey can be done on a group of people, asking them what drink they consume more of: tea, coffee, or soda. Most people consume coffee more often, which might be why it leads to the most discoloration. All three liquids have harmful sugars, but coffee is the most commonly and most frequently drank among the three.

The egg shells darkened to a point that the color reflected the color of the liquid they were in. The shell not in anything stayed the same, being the constant. The tea shell reflected the color of the week old tea. The coffee shell ended up becoming the color of coffee and the same for the soda shell.

Documents

The following links lead to various aspects of the project.

Science Fair Research Paper - "The Cause of Tooth Decay and Discoloration"

https://docs.google.com/a/laceyschools.org/document/d/12G3aXfUjYcqpezr2bwlT9YTtfA3TIkwJ85-t9H4D9G0/edit?usp=sharing

Science Fair Journal - "Which Drink Stains the White of an Egg the Most?"

https://docs.google.com/a/laceyschools.org/document/d/1_WUU_HoyxIaJOUFZzuWvJBBSPha2YKsDk3CTAgHNnJ8/edit?usp=sharing

Science Fair Presentation - "Which Drink Stains the White of an Egg the Most?"

Results

All of the egg shells within the liquids were stained a certain color. The severity of the staining depended on which liquid the shell was encased in. The shell in no liquid stayed the same off-white color it was originally. The shell inside the tea ended up staining only slightly in a light brown. The shell in the coffee stained a medium brown. The shell in the soda was stained the darkest brown. The color of the shell became similar to the color of the liquid it was in. The darkest liquid, soda, stained the shell the darkest brown while the lightest liquid, tea, stained the shell very light brown. The tea and coffee were still discoloring the egg, but it wasn’t as severe as the soda. Over the course of seven days, the drink that stained the off-white color of the egg shell the most was Coca-Cola soda.