Describe the set up and your methodology. Were all beakers to have the same concentration of yeast and of molasses, so each beaker was an alleged identical to each other beaker? Or did each beaker have a diff. conc of yeast and or molasses? All done at the same time?
Nevermind the .pdf attempt, this is easier, though it looks a little off.
The Effect of Temperature on the Rate of Carbon Dioxide Production in Saccharomyces
Abstract
We have concluded that a pH between 5 and 6 is best for fermentation for alcohol by using various pH levels in five different test tubes. By recording their starting conditions and then measuring their results afterwards, we will be able to see how much CO2 was produced, showing us which starting pH is most effective.
Introduction
Homo sapiens have been using fermentation to create alcoholic beverages for many years now. In this paper I will discuss which pH balance works best to this end. Carbon dioxide production in yeast can be affected by temperature and potential hydrogen, pH. I will be using five different beakers to with varying starting levels of pH. They will all be incubated at the same temperature at the same time while having pH levels that are different. In this lab, we will have no direct method of measuring gas. We can instead use water to show how much CO2 was made and the fermentation rate (Schweinitz).
Materials
· 1 medium beaker (approximately 300-500 ml capacity)
· 5 small beakers labeled 1 through 5 (80-120 ml capacity)
· 5 fermentation tubes labeled with group letter and numbered 1 through 5
· 1 medium graduated cylinder (50 ml)
· 1 small graduated cylinder (10 ml)
· 1 hydrometer and hydrometer tube
· 5 glass stirring rods
· Wax pencil
· 2.0 M Citric acid solution (dropper bottle)
· 0.3 M Calcium hydroxide solution (dropper bottle)
· pH paper test strips
· gloves (latex)
Method
The first step was to pour 150 ml of the yeast/molasses mixture into a medium beaker while continuously stirring the flask.
The second step was to take the beaker to the lab table while continuing to swirl. We used the graduated cylinder to transfer exactly 30 ml of the mixture into each of the 5 beakers which we labeled 1 through 5. All of the beakers received the same quantity and concentration of the yeast/molasses mixture.
Thirdly, we used pH paper which helped us to ascertain the pH of the mixture in beaker 3. The pH was recorded at 5. Beaker 3 became our control mixture and we never changed its pH level. We would record the data.
We next added citric acid, given a few drops at a time to beaker 2, stirring and checking pH until we reached a pH of 4.0. We recorded the data.
We then moved on to baker 1, adding the same number of drops of citric acid as used previously. This continued until a pH of 2.0 was given. Data was recorded.
Now we moved on to beaker 4, adding calcium hydroxide this time. We got the pH of beaker 4 to 8.0. We also did this to beaker 5, only we upped the pH to 10.0. All data was recorded.
For our next step, we measured and recorded the specific gravity of beaker number 3 by using a hydrometer. All beakers had the same specific gravity and so we recorded it thusly. To record the specific gravity, we poured the yeast mixture form the beaker into the hydrometer tube until it was two-thirds of the way full. We then inserted the hydrometer without letting it hit the bottom of the tube whilst also dislodging any bubbles. After recording the specific gravity, we removed the hydrometer and returned the mixture to the beaker.
At this point we returned the solutions from the five beakers to the appropriately labeled fermentation tubes without any bubbles.
All fermentation tubes were then placed in the incubator at time 1939, where they would be incubated at 45C until a time of 2045, a time of 46 minutes.
Immediately after removing the fermentation tubes from the incubator, we marked the gas level on the fermentation tube with a wax pencil after ensuring that the tubes were sitting flat on the table so that we could be as accurate as possible.
We then documented that 46 minutes had passed since incubation first began.
After that, we poured the contents of the fermentation tube into the hydrometer tube and measured the final specific gravity.
At this point we measured the volume of gas collected in the fermentation tube by adding a small amount of water to the tube and then inverted it so that the water leveled off to the mark we made earlier. By moving the water to a graduated cylinder we were able to record the volume of CO2 by measuring the water. We did this for all of the fermentation tubes and recorded the data.
Hypothesis
Each difference in pH will yield a varying amount of CO2.
Prediction
I predict that the best pH will be between 5 and 6; this correlates to beaker 3.
Results
Citations
Schweinitz, Jean.
Majors Biology Laboratory Manual. Second Edition. 2009, 2010. Kendall Hunt Publishing Company.