1. The Effects of Acids on Seashell Corrosion Carla Giannandrea Academy of Notre Dame de Namur

2. Question What will happen to the percent change in the mass of seashells when soaked in different acid solutions?

3. Background Information Earth’s oceans absorb the carbon dioxide in the air emitted by humans. The acidity level of water has risen from 8.2 to 8.1 Acids are considered either strong or weak There are three types of acids, monoprotic, diprotic, and tripotic acids. Seashells are comprised of three shell layers... Proteinaceous periosteum Prismatic layer Inner pearly layer of nacre

4. Hypothesis The percent change of the mass of seashells will increase as the pH levels of the different acid solutions decrease

5. Materials 72 seashells Balance 36 large glass jars pH meter HCl (Hydrochloric Acid) H 2 SO 4 (Sulfuric Acid) HNO 3 (Nitric Acid) Distilled water

6. http://sciencetools-w310.wikispaces.com/file/view/1w310_005.JPG/125401779/1w310_005.JPG

7. Procedure Three different solutions of 500 mLs of HCl were made, each with different pH level Each solution was then put into a different jar. Steps one and two were done with acids HNO 3 and H 2 SO 4 as well. Distilled Water was put into nine different jars. The seashells were massed and put into the solutions for seven days. When taken out, they were massed again and the percent change in mass was found in each seashell.

8. Independent Variables Different types of acids Different pH levels of acids Dependent Variables Percent change in the mass of the seashells Control Seashells soaked only in distilled water Constants Approximately same sized seashells Same amount of solution in each jar Soaked for the same amount of time Maintained under tha same conditions

12. T-TestP. Value Distilled Water to HCl ph 50.043 Distilled Water to HCl ph 40.043 Distilled Water to HCl ph 3 0.681 Distilled Water to HNO3 ph 50.168 Distilled Water to HNO3 ph 40.765 Distilled Water to HNO3 ph 30.938 Distilled Water to H2SO4 ph 50.745 Distilled Water to H2SO4 ph 40.978 Distilled Water to H2SO4 ph 30.191

13. Discussion and Analysis

14. Conclusion The results of this experiments concluded that short term exposure to acid solutions does not affect the mass of seashells. A source of error could have been inaccurate readings of the pH meter when making the solutions.

15. Further Research Testing change in softness of the seashells instead of change in mass Using different types of seashells Using a control with pH 8.1 (the pH level of the ocean) Using a control of salt water instead of distilled water

16. References Acid. (1990). In S. P. Elliot, M. Goldstein, & M. Upshall (Eds.), Webster’s New World Encyclopedia (9th ed., p. 7). United States of America: Prentice Hall. (Original work published 1948) Acid and Base Chemistry. (n.d.). Retrieved October 6, 2002, from Shoder website: http://www.shodor.org/unchem/basic/lab/ http://www.shodor.org/unchem/basic/lab/ Acids. (n.d.). Retrieved October 6, 2010, from http://hyperphysics.phy-astr.gsu.edu/hbasic/chemical/acid.htmlhttp://hyperphysics.phy-astr.gsu.edu/hbasic/chemical/acid.html Bivalve Shell. (n.d.). Retrieved from http://en.wikipedia.org//_shell Brewer, P. G., & Barry, J. (2008, October 7). Rising Acidity in the Ocean: The Other CO2 Problem. Scientific American. Retrieved from http://www.scientificamerican.com/.cfm?id=rising-acidity-in-the-ocean&page=2http://www.scientificamerican.com/.cfm?id=rising-acidity-in-the-ocean&page=2 Carpi, A. (n.d.). Acids and Bases. Retrieved 2003, from http://www.visionlearning.com/library/module_viewer.php?mid=58 Chemistry (A. C. Wilbraham, D. D. Staley, M. S. Matta, & E. L. Waterman, Trans., pp. 271, 589-591, 600-607). (2008). Boston, Massachusetts: Pearson Prentice Hall.

17. References (continued) Hardt, M. J., & Safina, C. (2010, August). Threatening Ocean Life from the Inside Out. Scientific American, 66- 73. Horne, F. (2006, October 23). How are seashells created? Or any other shell, such as a snail’s or a turtle’s? [Special section]. Scientific American. Retrieved from http://www.scientificamerican.com/.cfm?id=how-are- seashells-createdhttp://www.scientificamerican.com/.cfm?id=how-are- seashells-created pH Indicator. (n.d.). Retrieved from http://en.wikipedia.org//_indicatorhttp://en.wikipedia.org//_indicator Seashells. (n.d.). Retrieved October 4, 2010, from Wikipedia website: http://en.wikipedia.org/wiki/Seashellhttp://en.wikipedia.org/wiki/Seashell Where do Seashells come from? (n.d.). Retrieved from http://www.seashellsandsuch.com/articles/wherecomefrom.php http://www.seashellsandsuch.com/articles/wherecomefrom.php