salivary acidity and temperature

[deleted-618788]

I would like to conduct experiment to investigate effect of varying temperature of oral liquids on acidity of saliva.I would like to use hot/warm/cold sports drink, milk, water, tea to investigate their effect on salivary acidity. I did not see any relevant articles in google scholar. Can someone guide me construct this experiment? Thanks

[EricBebenov24]

Hello, very interesting science experiment.

One consideration you might want to take are some of the ingredients that are contained in the liquids you will be using. Sugar, for example, is known to increase acidity. So, if you are using sports drinks which might contain sugar, this might skew your results because you are trying to find out how the temperature of the liquids affect acidity, not the effect the ingredients have on it. You might use cold, warm, and hot pure water to avoid any ingredients which might affect the acidity. By doing so, you will be able to see how only the temperature affects acidity, and not any other ingredients contained in the liquid. You can formulate a hypothesis before you actually start testing your experiment.

When conducting the experiment, you could utilize pH strips, which change color depending on the pH of what you are measuring, in this case, saliva. First, you could swirl a cold liquid in your mouth, free of any ingredients which might skew your pH, and place a sample of saliva on the strip after spitting out the liquid. Next, you could use the same liquid, but with a warmer temperature. This could mean slight heating. Once again, after spitting out the warm liquid, place a sample of saliva on a pH strip and watch the color. Finally, heat the same liquid until it is hot, but be careful when swirling it in your mouth so it does not cause any burns. Make the temperature of the liquid hot, but tolerant for you to put in your mouth. Place the sample of saliva on the pH strip and watch the results. After a couple minutes, you will be able to see what the color of each pH strip is. You can repeat this for several more trials to ensure accuracy.

After experimentation, you will be faced with data, which could be formulated into a scientific theory, potentially building onto your initial hypothesis.
Here is a link to the Science Buddies Scientific Method page, which could further help you in organizing your experiment:
https://www.sciencebuddies.org/science- ... fic-method

I hope this information helped answer your question. Feel free to ask any other questions which might come your way, and hopefully you enjoy your experiment.

Sincerely,
EricBebenov24

[deleted-618788]

Hello Eric,

Thanks for your thoughtful analysis and suggestions.
I do understand that sugar content of the liquids ingested will affect the acidity of saliva. But I plan to keep the sugar content constant and will change temperature only. I will compare results with cold vs warm vs hot liquid with same sugar content. Do you think that will work? Thanks

[EricBebenov24]

I am glad it helped!

If you would like to examine acidity of saliva solely on different liquid temperatures, I would suggest just using pure water since the sugar might start acting like an independent variable. If you decide to use a constant amount of sugar, even though the temperatures of the liquids will be different, the acidity of saliva would be significantly high in all three of the cups due to the sugar contained in them, not providing much of a relationship between temperature and saliva acidity since sugar acts as a confounding variable, or an outside influence which skews your experiment. The sugar, although constant, would still be in the way of observing the relationship between liquid temperature and salivary acidity. However, if you would still like to add a constant amount of sugar, you could shift the main idea of your experiment. Instead of examining "How does the temperature of a liquid affect salivary acidity?", your new question could be "How does sugar affect salivary acidity when it is present in variant temperatures of a liquid"? I hope you are able to see the difference.

If you still have any questions, do not hesitate to ask.
I hope this answers your question!

[deleted-618788]

Eric, I reviewed your reply. I will probably use only water as a liquid to avoid confounding variable. Can you tell me what should be my sample size? In other words, how many observations should I take in my experiment? What statistical method I should use to find significant differences in my observation? Thanks

[deleted-618788]

Eric, I also want to know whether there should be control group in my experiment. Thanks

[EricBebenov24]

Sorry,
I thought I replied, but my message did not send.

What you could do is conduct multiple trials to be able to gather a large sum of data. This would ensure that your data is consistent, therefore avoiding any errors. For example, you can conduct four trials that examine the salivary acidity for each water temperature. After you finish your four trials, you can then take the average to get one average trial. When it comes to observations, you can decide what you want to observe. You have been observing the salivary acidity in comparison to different water temperatures, so that counts as an observation. If you want to observe other things, you decide what they would be.

The statistical method you could use is descriptive statistics, which summarizes your data numerically. This method would allow you to take the mean, median, mode, and range of the salivary pH data, for example. If you decide to use this statistical method, more trials would be suggested since it would give you more data to deal with.

A control group is not necessary, but it does serve as a way to see the extent the independent variable has on the experimental group. It serves as a comparison. In your experiment, the independent variable would be the temperature of the water, and the dependent variable would be the resulting pH of the saliva. In your control group, you could just keep the temperature of the water at room temperature, not being hot or cold. This would allow you to see how the salivary pH is affected without any major extremes in temperature. It is good to have a control group, so I would suggest it.

I hope your experiment goes well, and feel free to ask for any clarification.
EricBebenov24

[deleted-618788]

Thanks Eric.
I have few more questions.
1. I need to use thermometer to check temperature of water. Any recommendation regarding type of thermometer?
2. Secondly, I will be checking average/ mean ph of water at cold, hot and room temperature. I need to compare means to see whether there is any significant difference between them. What statistical test should I use to compare means? Can I use student t test?

[EricBebenov24]

For your first question, digital thermometers are said to be very accurate, so you might consider using this type of thermometer. However, if you don't have a digital thermometer that measures the temperature of water, that's fine, any thermometer would work, but might not be as accurate. I will answer your second question shortly.
For your second question, you can use an "Analysis of Variance" (ANOVA) test which is used when you have two or more means. This test will tell you if there are any statistically significant differences between the means that you have measured. In your case, you will be comparing the salivary acidity pH for the three different water temperatures that you will be utilizing. So, a t-test would be useful when you are comparing two different groups, like hot and cold water, but since you want to have a water temperature in between, you would use the "Analysis of Variance" test to be able to include this third temperature.

[deleted-618788]

Eric, thanks for your input. I looked up ANOVA on excel. There are 3 options for ANOVA
1. ANOVA single factor
2. ANOVA 2 factor with replication
3. ANOVA 2 factor without replication
Which one would be suitable for my project? Thanks

[EricBebenov24]

Since you are only looking at one independent variable, water temperature, you can use the standard Anova Single Factor. If you decide to include other independent variables that could affect the salivary acidity in your experiment, then you can use the other two.

[deleted-618788]

Eric, I would like to use water, tea and black coffee without cream or sugar. I would subject to drink these liquids at hot, room and cold temperatures. I will check Ph of saliva 5 minutes after drinking these liquids. Should I ask subject to drink/swallow these liquids or spit it out?

[EricBebenov24]

Hi,
It really does not matter if they spit the drink out or decide to swallow it. As long as the liquid is able to make contact with the saliva, then that's fine. However, I would suggest that the salivary pH is measured right away instead of waiting for five minutes because when the hot liquid is ingested, the saliva might experience significant cooling after the five minute period. So, you could wait a couple of seconds instead of five minutes. Also, you might want to avoid eating or drinking half-an-hour before your experiment to avoid any other foods and beverages that might skew the salivary pH. As well, conducting the trial with the room-temperature liquid first would ensure that the hot and cold temperatures do not alter the salivary temperature after exposed to the room temperature liquids. For example, if you conduct the trial with the hot water first and then proceed with the room temperature, your mouth would have some initial heat, so doing the room-temperature first would avoid this error.

I hope these suggestions make sense,
If they don't, feel free to ask!

EricBebenov24

[deleted-618788]

Eric, thanks again for your guidance. I have a question about quantity of fluid (water, coffee or tea) to be consumed or swallowed? Should it be 1 sip or 1 cup? Any suggestions?

[EricBebenov24]

No problem,
To ensure that all of the saliva has been mixed and exposed to the liquid, add a sufficient amount that could be thoroughly swirled in your mouth. For example, if you add too little, the saliva sample would not be representative of the liquid temperature. Therefore, add a sufficient amount so the saliva sample could undertake the temperature of the liquid, which would then be used to measure the pH. One cup would be the recommended.

EricBebenov24

[deleted-618788]

Eric, I am going to use water, coffee and tea as liquids to be investigated at different temperatures. Coffee and tea will be without cream and sugar. Can you think of any other liquids that I can use? I would prefer to use liquid that does not have any carbohydrates. Thanks

[EricBebenov24]

Water, coffee, and tea would be sufficient liquids to use in your experiment. Other liquids you might consider could be ones in which not many ingredients are present, minimizing potential error, as well as liquids which are low on carbohydrates.

[deleted-618788]

Eric, what should be my control group? I am going to use water, tea and coffee. Is water my control group?

[deleted-618788]

Eric, is there a possibility that ph change will occur maybe 15-20 minutes after being exposed to liquids with high/low temperatures? I am worried about it as you recommended checking ph immediately after drinking liquids with different temperatures.

[EricBebenov24]

Your control group would include the saliva that is not exposed to any liquid temperatures. So, you could just measure the pH of saliva without any liquid additives containing various temperatures, which means that water would not be considered the control group. Also, for each trial, keep the liquid you are using constant. This means that for hot, cold, and room temperature, use the same type of liquid. You could do one trial using the coffee for all three temperatures, a trial using water for all three temperatures, and a trial using tea for all three temperatures. After that, you could repeat it once more to get two trials for each type of liquid.

Regarding how long you should wait before checking the pH, you should do it almost right away. For example, if you wait 20 minutes to check the salivary pH after being exposed to the hot liquid, the saliva would experience significant cooling and would yield similar results to that of the room temperature liquid. The salivary mixture with the hot liquid would no longer be hot, since the 20 minutes that you were waiting allowed it to cool down.
Please ask if you need any clarification!


EricBebenov24

[deleted-618788]

Eric, thanks for your input. One more question. Do I have to do ANOVA test separately for each liquid(coffee, tea, water)?

[EricBebenov24]

Your independent variable would be temperature, which would then be subdivided into cold, room temperature, hot, and your control group. If you would like to compare your results for each type of liquid and have it accessible in one spot, then you could keep all three of them in one ANOVA test. If you would like to keep the results separate without comparing the results for each liquid, then you could do them in separate tests. You could also do a separate test for each liquid and then compare each of the tests individually. Therefore, if you want to closely compare them, keep them in one test, or if you would just like to look at each liquid individually, then you can make separate tests.