Ice Nucleation Essay

540 Words3 Pages
Title Section: Ice-Nucleation BIO 115 (Tuesday 10:30) Introduction: Ice nucleation, what is it? Well nucleation is the initial trigger that allows freezing, the formation of ice crystals, to progress. Any compound at the appropriate temperature will change its state from a liquid to a solid. The bacteria added to the solution will act as the nucleus for the formation of the ice crystals given the right conditions. Pseudomonas syringae is a rod shaped gram-negative bacterium with polar flagella. As exemplified with the preliminary results it appears that PS uses its gram-negative poles to attract the hydrogen, making the molecules more compacted together. So in assuming, Pseudomonas syringae will group together the solution’s molecules causing its phase state to change from a liquid to a solid. Knowing that as an example, will all other rod-shaped bacteria trigger ice nucleation. Escherichia coli will be used as a second rod-shaped bacterium to prove hypothesis, and nutrient bath will act as its control. Methods: To begin, 3 test tubes were filled with ~4 mL of the distilled water solution and placed in an ice bath with ~50mL of 70% ethanol. Then, 100mL of Pseudomonas syringae, nutrient bath and ionized water were added to different test tubes and whether there was a phase change or not was recorded. This was treated as the preliminary test. Next 3 more test tubes were filled with ~4 mL of the distilled water solution were placed in the same ice bath. Finally, 100mL of Pseudomonas syringae, nutrient bath and Escherichia coli (instead of ionized water) was added to different test tubes and whether there was a phase change or not was recorded. This was treated as the student designed test. Results: In the preliminary test it was determined that when Pseudomonas syringae was mixed with distilled water the solution formed ice crystals. But there
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