1. © File copyright Colin Purrington. You may use for making your poster, of course, but please do not plagiarize, adapt, or put on your own site. Also, do not upload this file, even if modified, to third-party file-sharing sites such as doctoc.com. If you have insatiable need to post a template onto your own site, search the internet for a different template to steal. File downloaded from http://colinpurrington.com/tips/academic/pos terdesign. Research Question What is the difference in acidity level (measured by pH) between less ripe and more ripe Navel Oranges? Technology, Materials, and Method Mettler Toledo FiveEasy Plus pH Meter 20 Navel Oranges Ripeness was determined using the following criteria; vibrant color, tender flesh (gives slightly when squeezed), high amount of wrinkles, heavy for its size. 20 Navel Oranges were randomly chosen from Walmart, and the 10 ripest were determined by the former criteria. The other 10 were considered to be less ripe. The oranges were randomly paired to compare pH. Each orange was rolled 3 times to liberate juices, before being cut into 3 roughly equal segments. The 3 segments of each orange were squeezed, and the juice was passed through a fine sieve to remove seeds and pulp. 10mL of juice was collected from each segment. Each aliquot of juice was put into a 10mL beaker and the pH was measured using a Mettler Toledo FiveEasy Plus pH Meter. The pH data from each aliquot was averaged for each orange. By: Jacob T. Schmied Date: 10/29/15 Scientific Research Poster Presentation 1.Carter, J. (Producer). (2012, November 14). How to Tell if Orange Are Ripe: Choosing Great Produce. Cooking Guide. Video retrieved from https://www.youtube.com/watch?v=yE4bVfPC6aA https://www.youtube.com/watch?v=yE4bVfPC6aA 2.Penniston, K. L., Nakada, S. Y., Holmes, R. P., & Assimos, D. G. (2008). Quantitative assessment of citric acid in lemon juice, lime juice, and commercially-available fruit juice products. Journal of Endourology, 22(3), 567-570. 3.Sinclair, W. B., Bartholomew, E. T., & Ramsey, R. C. (1945). Analysis of the organic acids of orange juice. Plant physiology, 20(1), 3. 4.Smith, G. (2014). Standard Deviations; Flawed assumptions, tortured data, and other ways to lie with statistics. New York, NY: Peter Mayer Publishers, Inc. RAP(ping)- Ripeness, Acidity, and pH of Oranges Data was analyzed in two ways; each pair of oranges was looked at and their pH’s were compared, and the average pH of all 10 more ripe and all 10 less ripe oranges were compared. Both ways of looking at the data clearly show that more ripe oranges are less acidic (higher pH) than less ripe oranges. A t-test for 2 sample means assuming unequal variance was done in Excel looking at the individual groups. This was done to ensure the values calculated are indeed different. The t-value was 8.97, and the critical t was 1.76 (alpha=.05). This means the two groups are very likely to be significant statistical difference. This t- test supports the finding that more ripe oranges have a higher pH than less ripe oranges. References Findings and Analysis Next Generation Science Standards Alignment HS-PS1-2. Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties. Research looks at patterns in chemical properties, with regards to the ripeness of oranges. Crosscutting concepts Patterns- Patterns in data can be observed in this research. The data is also thoroughly analyzed to ensure the patterns are truly as they appear, and not just tricks of the graph. Cause and Effect- After looking at this data, students can take the next step of asking why there is an pH difference observed due to ripeness. The pH of more ripe vs. less ripe oranges is clearly different. Only in one pair of oranges was the less ripe orange less acidic. This could be due to flaws in the method of picking more vs less ripe, because the methods were purely qualitative and based on the opinion of only one person. Looking at the aggregated data, the pH of more ripe oranges was 5.19, and the pH of less ripe oranges was 4.71. This difference seems minute. However, pH is measured on a logarithmic scale. A pH difference of 1 means something is 10 times more or less acidic. The difference in more vs less ripe is 0.48. This means that more ripe oranges are 4.8 times less acidic than less ripe oranges. This difference is significant in a couple of ways. Most obviously is the flavor of the oranges. Considering that acidic things taste sour makes sense for less ripe oranges. Less ripe, lower pH, more acidic, more sour flavor. Comparing the pH’s of less and more ripe oranges gives a reason why more ripe oranges taste better; their pH is higher, so they are less sour. The acidity difference is also significant because citric acid can be useful in nutritional therapy for calcium urolithiasis (kidney stones) 2. Citric acid is the main acidic chemical in oranges, meaning that most of their acidity is due to the presence of citric acid. Citric acid is also one of the main compounds that is broken down as oranges ripen 4. This means that less ripe oranges, due to their higher concentration of citric acid, may be more useful for the nutritional treatment of chronic kidney stones than more ripe oranges would be. Data was looked at in two ways to avoid Simpson’s Paradox. Simpson’s Paradox is when the patterns in aggregated vs. disaggregated data are reversed 4. By looking at the data in pairs of oranges and comparing each pair, and looking at more ripe and less ripe groups as a whole, it can be seen that Simpson’s Paradox is not present in the data. Conclusions and Discussion