Nt1310 Unit 3 Lab Report

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Pages: 5

1. Set up a total of 18 test tubes, placing 3 test tubes in each of the 6 test tube racks; one test tube rack for each variable. This includes 3 test tubes for each variable to find an average and reduce the effect of anomalies making the results more reliable.
2. Then using a pipette extract 4ml of algal solution (Tolypothrix) from the beaker and place in a test tube. Repeat this for all 18 test tubes making sure that the measurement is read from the meniscus to ensure reliability.
3. After this, using a new pipette place 2ml of pH4 buffer in each of 3 test tubes in one test tube rack, and insert a bung immediately to avoid contamination.
4. Repeat this with a set of 4ml of pH4, 2ml of pH5, 4ml of pH5, 2ml of pH6 and 4ml of pH6 buffer. Make sure to label each test tube clearly so that later you can tell which test tubes contain
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Leave the samples in sunlight under lamps so that the Tolypothrix can constantly photosynthesise for 48 hours.
9. Then repeat using the colorimeter the same way as before, to find an average of the absorbance for each variable, giving us the final absorbance.
10. Therefore now compare the results between the initial and final absorbance to see the effect the variable had on the growth.
CARBON DIOXIDE
1. Using a pipette extract 15ml of Tolypothrix solution and place in a 1000ml beaker. Then repeat into another beaker so that you have two beakers each containing 15ml of Tolypothrix.
2. Label one beaker 350 ppm and the other 950 ppm.
3. To create the Carbon dioxide to change the PPM, react 2 grams of Calcium Carbonate with 10cm3 of Hydrochloric acid. Connect this with a capillary tube to a syringe and collect the carbon dioxide.
4. Then using the syringe insert the certain amount of gas into the 950 ppm labelled beaker so that the concentration of carbon dioxide reaches 950 ppm.
5. Seal the beakers with cling film and tape so that nothing enters the test tube nor can the ppm be affected by the outside air, hence it is air