Tea Related Science Fair Project HELP!URGENT!

[deleted-336520]

Hi everyone,

For our Science Fair project, we did this experiment where we tested to see if which different types of tea would stain your tea the most. We got green tea and handed that in for our Science Fair Project Abstract. However, upon further research, every single website said black tea would stain your teeth the most. HELP? WHAT SHOULD I DO ? I don't think I did anything wrong with my experiment , How do I defend my project in Disscussion part of the report ?

From,

[SciB]

You didn't say how you did the experiment so I can't say anything about it. But in science, there are no 'right' results. What you get is what you report. Many times our data disagree with what others have found and sometimes it turns out that they were wrong.

Not all green tea is the same just as not all black tea is the same. You cannot say that something is wrong with your experiment because your results did not duplicate someone else's results. How many people did you test? How long did you run the experiment? There are many variables that are difficult to control like whether people were eating while they had tea, whether they added milk or a non-dairy creamer, whether they did or did not brush their teeth after drinking tea, etc, etc.

Report your findings and describe your methods exactly. Compare your results to other reports and discuss the differences in method, number of test subjects, type and amount of tea, time of drinking, etc. Finally, give your conclusions and propose some further experiments with better controls, more subjects, more controlled variables, or different teas to improve the quality of your data. That is how science works to continually increase our understanding.

Sybee

[donnahardy2]

Hi annayxia2002,

Welcome to Science Buddies!

This sounds like a great project. I can assure you that you did not do anything wrong. Results of a science experiment are empirical; they are what actually happened so you should not worry about this and you should not change your results.

You did not include any details about how you did your experiment and that would be helpful in understanding what happened. Your discussion section will be important for the science fair judges because you do need to explain why your results are different compared to previously reported results. If there is a little time before your project is due, please describe your experimental set up.

First, in you background reading did you find any explanation about how tea stains teeth? If so, do you know what the difference is between green and black tea and why there might be a difference in results?

Here are some questions that might help you to explain the results,

1. What did you use for the tooth substrate? What there any difference in the material used for staining?
2. How did you make the tea? Could there have been a difference in the concentration of teas used?
3. Did you incubate the teeth in the tea for the same amount of time? Were all other conditions in the experiment controlled (identical)?
4. Did you run the experiment in duplicate or triplicate or did you repeat your experiment more than one time. Repetition always helps confirm results.
5. How did you measure the staining? Was your test quantitative, or did you have independent observers evaluate the results?

It is possible that your results are correct and everyone else has been wrong, so you should state your conclusion if the experiment was controlled and you were able to measure results. If you think that the experimental protocol was flawed in any way, then you should state what you would do differently if you were to repeat it in the future.

The discussion section for this project will be very important, so I hope these ideas will help. Do let us know more details about your experiment if you need more suggestions.

Donna Hardy

[deleted-336520]

Thank you so much for replying!
We used eggshells as a substitute for teeth, but we didn't hollow it out. Also, we had used room temperature water, and once we poured water into each bowl, we let it soak for 5 min. Then we put the eggs in as fast as we could and let that soak for a day until we took it out for observations. We did six trials and the determination of which was stained the most was on personal opinion.
Though obviously, we couldnt put the eggs in at the same time, take them out at the same time, pour water into each bowl at the same time, etc. I dont really think that it would affect the results that much. Was it because there was an egg in the eggshell? Or maybe the water was room temperature and not hot?

Apparently, there are these things called tannins in tea, and they are organic substances that cause staining. Then theres catechins, thearubigins, and theaflavins that are some types of tannin, and also affect the stains left on teeth
(eggshells).

This is our current discussion. Any advice on making it better?
Discussion

In our project we used eggshells as a representation of teeth and soaked it in varying types of tea for a day. After our experiment, we found out that green tea stains our teeth the most. Because it was green tea that stained the eggshell the most, we had to reject our hypothesis which stated that black tea would stain our teeth the most. We think that green tea had stained the eggshell more than black tea, because there are more catechins in green tea. And because there are more catechins, they may have converted to thearubigins when they were soaked in water, causing the eggs to be stained a reddish color.

Some shortcomings in our experiment were that when we placed the eggs in the bowls, our fingers brought out some tea leaves. Also, we could not pour water in all six bowls simultaneously which meant that some teas would have longer to soak than others. The same problem also occurred with the placement of the eggs in the tea, and the process of taking the eggs out of each bowl of tea after the period of a day.

After researching other websites,we found that they all stated that black tea would stain your teeth the most. However our results states that green tea stains more than black tea. The brand of tea we used may have affected the results, along with the fact that there was an egg inside.


Thank you guys so much!
Anny

[donnahardy2]

Hi Anny,

Thanks for the details. This is helpful.

You did a great job in background research on the composition of tea and identifying the compounds that might be interacting with the eggshells.

It sounds like you did a good job of controlling all parameters other than the tea, which was your independent variable. Can you verify that you used the same quantity of green and black tea in the experiment?. If you did, this will help support your conclusion that green tea stains more than black tea.

If you soaked the eggs in the tea for a whole day, then a few minutes' difference in timing would not make any significant difference in results. If you did six trials, then your results were reproducible, even though results were qualitative (personal opinion). If you had more than one person evaluate the results, your conclusion would be stronger. Did you take any photos that show the difference in color compared to a control (unstained eggshell)?

Eggshells are composed of calcium carbonate and teeth are composed primarily of calcium phosphate, so the chemistry is a little different. However, your experiment is still valid because the polyphenols and tannins in tea probably interact with the calcium. You should mention in your discussion that you would have preferred to use real teeth in your experiment, however this was not possible. If you decide to continue this investigation in your next year's science project, I recommend switching to something like chicken bones, which are composed of calcium phosphate, but don't have the enamel coating that teeth do.

Here is a reference article that may be useful for your discussion: The introduction section (the paragraph under figure one, mentions that tea polyphenols bind to metal ions.. Calcium is a divalent cation and classified as an alkaline earth element and it would probably interact with all of the OH (hydroxyl ions) on the polyphenols and catechins in tea.

http://jn.nutrition.org/content/130/10/2409.full

Your conclusion is good because you stated that you had to reject your original hypothesis. You should explain that green tea apparently has more of the compounds that interact with calcium, so your results are valid.

You should also add a short statement about how you would do the experiment differently, if possible. Perhaps you could use calcium phosphate as a substrate and include more varieties of green and black tea. You would also want to find a way to measure your results.

You did a great job on this experiment! Please let us know if you have any other questions.

Donna Hardy