Investigating Fermentation-Making Kimchi (Teresa Glass)
Research Question and Hypothesis
How does fermentation affect PH?Ph will increase due to Alcohol Fermentation.
Standards
HS-LS1-6.
Construct and revise an explanation based on evidence for how carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules.[Clarification Statement: Emphasis is on using evidence from models and simulations to support explanations.] [Assessment Boundary: Assessment does not include the details of the specific chemical reactions or identification of macromolecules.]
HS-LS2-3.
Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions. [Clarification Statement: Emphasis is on conceptual understanding of the role of aerobic and anaerobic respiration in different environments.] [Assessment Boundary: Assessment does not include the specific chemical processes of either aerobic or anaerobic respiration.]
Experimental Design
Kimchi will be made by allowing microorganisms to ferment Chinese Cabbage?
Independent variable
The independent variable is the temperature. a thermometer will be used.
Dependent variables
The dependent variables are the microorganisms and the Ph. The Ph will be measured using PH filter paper.Temperature will measured using a thermometer. finally each bag of kimchi will be given a different amount of salt. One bag will have 1/2 tsp. of sal and the other will have one teaspoon of salt.
Series
I will be studying ph as a function of time .
Constants and Controls
The microorganism is a constant. Time serves as a control. Temperature also serves as a control.
Materials
Two resealable plastic Sandwich bags. 2.5 ml. (1/2 teaspoon) Measuring spoon
Chopped Chinese cabbage p-h indicator paper
Non iodized salt Thermometer
Procedures
1.Take the two plastic sandwich bags and place one resealable bag inside the other.
2 .Fill half of the inner bag with Chinese chopped cabbage. Place 2.5 ml of salt inside the inner bag. seal both bag and turn the bags upside down to mix the ingredients. turn the bags upside down several times.
3. unseal the bags to press down on them and expel any air.then reseal the bags. label the bags of Kimchi with your name and place them in a cool area where they will remain undisturbed . Make a data table listing days, ph, temperature, and observation. Make columns on the data table for two weeks. Measure and record the air temperature on your data table. Wash your hands at the end of each lab period.
4. Each day, observe the kimchi in the bags.Record your observations of the changes in the appearence of the kimchi or the bags in your data table. When a small amount of liquid appears in the bottom of the inner bag, open the bags. CAUTION: Do not eat the kimchi.
5. Use ph indicator paper to measure the ph.Record ph in your data table.
6. Press out any gas in the bags and reseal them. return the bags to the cool area and leave them undisturbed for a week.
7. One week after you measured the ph repeat steps five and six.Then move the bags containing the kimchi to your refrigerator.Record the temperature of the refrigerator in your data table. Continue to observe and record the kimchi and records its ph every week for four weeks.
Sample data and graphs
IAnalysis & Conclusions
Use your data table to construct a graph showing the relationship of ph to time. What substance do you think was responsible for the change in ph.?lactic acid was probably responsible for the change in ph as it is found on Chinese cabbage..What process could have produced this substance?Lactic acid fermentation produced this substance as the bacteria found in Chinese cabbage produces lactic acid..Was your prediction correct?Yes, the ph increased over time but it did not increase by much. It was still acidic.What changes would you make in your hypothesis as a result of your observations? The ph did not increase by much and it was still an acid.The ph did not change too much as time passed.Did you see any evidence that a gas was produced or consumed in the bags?Condensation occurred in the bags and there was a foul odor. If so what was this gas?The gas was probably methane because the kimchi was decaying.What process was responsible for this change? The lactic acid was responsible for this change as it occurred over a period of a month. The lactic acid contributed to the decay. Explain the reasons for your answers.
Photos & Movies
References
http://www.phschool.com/webcodes10/index.cfm?wcprefix=cbd&wcsuffix=3094&area=view