Formal Lab Report Essay Example

Formal Lab Report Essay Example Formal Lab Report Essay Formal Lab Report Essay Once we gathered exactly 12 brine shrimp, we then dumped the contents of the cylinder, including the brine shrimp, into the Petri dish labeled C' for control. We continued to use the pipette to gather 12 brine shrimp and measured the level to 20 ml for each of the other Petri dishes until each Petri sis contained 12 brine shrimp each. Step 4- Before adding any of the concentrations to the Petri dishes, we put the lids on all four of the Petri dishes and set our Stop watch for 5 minutes to observe the brine shrimp in their controlled atmosphere. Once 5 minutes ended, we then counted the number of live brine shrimp and recorded the information on a chart for each individual Petri dish. This was very important because brine shrimp are known for cannibalistic behaviors and losing a brine shrimp to cannibalism would throw off the count of live shrimp after the concentrations have been deed. Step 5- We discussed how affective we thought each concentration would be towards the brine shrimp. Our hypothesis was that ammonia will have the highest LLC-50 (toxicity), bleach will have the intermediate LLC-50 (toxicity) and vinegar will have the lowest LLC-50 (toxicity). : Step 6- Once the hypothesis was made, we gathered our dropper bottles of ammonia, vinegar and bleach. Leaving the C (control) Petri dish aside, we began adding the proper chemicals to the assigned Petri dish using a clean pipette pump assigned to each chemical. Each person was responsible for one Petri dish cause the chemicals had to be added at the same time to get accurate results. The Petri dish labeled V was given 0. 5 ml of vinegar, the Petri dish labeled B was given 0. 5 ml of bleach, the dish labeled A was given 0. Ml of ammonia at the same time and then we gently swirled the liquid in the Petri dishes and quickly replaced the lids and began the stop watch for 5 minutes. Step 7- Once 5 minutes was up We counted the number Of live brine shrimp in each Petri dish and calculated the concentration percent and mortality rate percentage. Using the number of live shrimp, we were able to calculate the umber of dead brine shrimp, which then allowed us to calculate the percent mortality rate at each concentration level. Because the brine shrimp were so small it was optional to use the magnifying glass or hand lens to be able to count the number of live brine shrimp in each dish. Formula for calculating concentration %: Niacin (Mimi) + brine (ml)= ml + amount of chemical added-? Total Volume NEXT (amount of chemical) / (total volume) x Formula for calculating mortality rate 96: (total dead) / (total starting number) x (1 % Step 8- We added another 0. 5 ml of each chemical to their signed Petri dishes a second time and set the stop watch for 5 minutes again. After the five minutes, we counted the number of live brine shrimp and calculated the mortality rate percentage. Step 9- Next began adding 1 ml of each chemical to their assigned Petri dishes, set the stop watch for 5 minutes and when the 5 minutes was over, we recorded the number of live shrimp and calculated the mortality rate percentage. We continued repeating this step, until a total of (five) 1 -ml aliquots had been added and the data was recorded. Step 10- Since the mortality rate for the brine shrimp in the Petri sizes labeled V (vinegar) and A (ammonia) had reached at least 80%, we could then end the test with that particular group of brine shrimp. The remaining Petri dish, B (bleach), had not reached at least 80% mortality rate so we continued to test it. Only this time, we had to begin adding 2 ml of bleach to the Petri dish and set the stop watch for 5 minutes and record data. This Step was done 2 times. Step 11- The addition Of 2 doses Of 2 mils was not changing the mortality rate, so we had to begin adding 5 mils and recording the number of live shrimp after 5 minutes and calculated the retaliatory rate percentage. This was done twice. F-anally on the third dose of 5 mils, we reached a mortality rate of at least 80%. We then recorded our final data. RESULTS: According to the data recorded we came out with different results than our hypothesis.