masson Posted November 25, 2008 Report Share Posted November 25, 2008 Hey guys. I have officially chosen Biology as my field of research for my Extended Essay. Initially I was planning to do the effect of UV light on yeast growth (ie. mayb during fermentation). But mentor said that is there any past research done? any info? I tried but not much. He said to pick a topic that would allow me to easily manipulate 1 variable and measure 1 variable. So after sitting down with mentor for 1/2 hour, I've got this so far: I have decided to use brewer's yeast for this. To activate the yeast, I have to put the yeast (in dormant stage) and put it in a solution of water and sugar. The yeast ferments the sugar and turns it into alcohol. So I have decided to change the PH level of the initial solution in which I have to put the yeast. So it RQ is along these lines: The effect of different pH levels of the solution in which the yeast ferment, on the alcohol production rate. I so I change the pH level of the solution which the yeast ferments and measure either alcohol production (mentor says that our school apparently has this thermometer like instrument, as you drop it into the alchol/water solution it floats to a certain level and can measure from there) or I can measure the carbon dioxide produce (can capture it using an apparatus commonly used in chemistry. Let me know guys. Thanks. Reply Link to post Share on other sites More sharing options...
Hedron123 Posted November 28, 2008 Report Share Posted November 28, 2008 Your research question should include the scientific name of the organism you are using. You could also use glucose or fructose (monosaccharides) due to the fact that if you use table sugar (sucrose) yeast would have to digest it and it affects your experiment a bit. In relation to your research question, I think it is appropriate to measure the volume of CO2 produced (with a data logger or otherwise) as it is a product of the process of alcoholic fermentation the yeast is carrying out. The question could be: To determine the effect of pH on the volume of CO2 produced by brewer's yeast ([i]Saccharomyces cerevisiae[/i]) as a result of alcoholic fermentation. Reply Link to post Share on other sites More sharing options...
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