- When you clean the equipment in the disinfectant do not make any direct hand to mouth reflexes, disinfectant can be highly dangerous if it was to get inside the human body and could easily result into death so when you are cleaning the equipment you must immediately go and wash your hands under warm running water using soap.
- When you actually complete the whole experiment you must wash the equipment and your hands and clean up the area where you was working, apple juice may have spilled and the tables could become sticky so that is something that you should definitely look out for, and also place your equipment back to their places.
Method/ Procedure:
-
When beginning your experiment you must firstly gather your equipment and set up your working area, when this is done you must then use the measuring cylinder to pour 100cm³ of apple juice into each of the 250cm³ conical flasks.
-
You should then use the syringe to put 4cm³ of yeast culture and 6cm³ of distilled water into the same 250cm³ conical flask containing apple juice in the conical flask.
-
Then replace the bung and delivery tube; the other end of the delivery tube should be placed in a 100cm³ conical flask containing the limewater.
-
You should now then draw up 6cm³ of sodium alginate solution into the syringe followed by 4cm³ of yeast culture and then mix the contents of the syringe by shaking it about and turning it upside down repeatedly.
- And at this point you must then release the contents of the syringe drop by drop into the beaker filled with calcium chloride solution, you must do this by holding the syringe nozzle 5cm away from the calcium chloride solution and press the plunger gently only allowing droplets out the nozzle of the syringe, you should notice the beads forming in the solution, after that you must place the syringe in disinfectant and wash your hands.
- Now you must filter the contents of the beaker using the filter paper and the funnel and the beads should remain in the filter paper, you should then rinse the beads with the distilled water.
-
Now carefully tip the beads into the other 250cm³ flask containing apple juice. Fit the flask with a bung and delivery tube. The other end of the delivery tube should be placed in the other 100cm³ conical flask containing limewater, and you must store the flasks in a warm environment.
Questions:
- What do you see forming as the drops fall into the calcium chloride solution?
Answer: As the drops fall into the calcium chloride solution I can see capsules forming inside the solution and they are gathering enzymes.
- What has happened to the yeast cells?
Answer: The yeast cells have been immobilised.
- What is the limewater for?
Answer: The limewater is there so I am able to identify if the yeast cells were immobilized, if the yeast cells were immobilized the limewater would turn cloudy.
- What is the difference between the contents of the two flasks?
Answer: One flask is used to tell us if the process of fermentation has taken place and the process of fermentation is occurring in the other flask.
- How will you know whether or not fermentation of sugar to alcohol has occurred in either flask?
Answer: You will know from when the limewater solution turns cloudy.
OVER A PERIOD OF 1-2 WEEKS…
- Has the limewater gone cloudy in either case?
Answer: Yes it has, it has become slightly cloudy in the limewater case.
- What do the contents of each flask smell like?
Answer: The flask filled with yeast cells and apple juice smells like alcohol and the limewater has a faint unknown smell.
Results:
After a few weeks I checked on my experiment again and noticed that:
- The limewater was cloudy; this must be a signed that the process of fermentation has taken place so I was successful in the experiment.
- I noticed the smell of alcohol in one of the beakers so yet again the fermentation process must’ve been successful.
- And also I noticed that the jelly like substance in the beakers captured the yeast cells and immobilised them.
Fair Test:
In order for me to make the experiment an fair test I could do the experiment three times and then see which two of them are the same, this way this would tell me that the third one that wasn’t the same must’ve been a faulty in the experiment.
I could also make it fair by using an thermometer to identify if the temperature of the solution was too high or too low, this way I would then be able to adjust it and then no errors would take place.
The factors that will affect my experiment are as followed:
- Temperature- The temperatures are not allowed to reach too high or else this will destroy the yeast cells and the temperatures cant reach too low because this will slow down the process of fermentation.
- Nutrients/ Food- The nutrients cannot be too much because if I feed them a lot then they will also release waste a lot and they will die from their own waste so the more food I feed them the quicker they will die depending on how much they are fed and also it will be a battle for the fittest in the tank.
- Oxygen Supply- The oxygen supply must always be up so that the yeast population are ale to perform the process of respiration, they need the oxygen because the oxygen acts like a catalyst and it speeds up the reaction.
Improvements:
Many thing can be done to improve our results such as changing our method on how we done the experiment, or maybe even using different equipment or we could also increase the amount of apple juice that we feed the yeast culture, below are things that I have identified that is essential in leading to an improvement for the experiment:
- Ph Sensor: - In scientific industry they use Ph sensors to identify and maintain if
The solution is neutral or not. (Neutral level= 7) It would be a good
Idea to add a Ph sensor to our equipment list, and this way we would
Be able to tell if the solution becomes to acidic or alkalinised and we
Would then be able to control and make it neutral.
- Air Supple: - Also in the scientific industry they use an equipment that pumps
Oxygen into the fermenter, which would then allow the yeast culture
To perform respiration, the added oxygen allows the process to
Quicken so this must mean the pumped oxygen acts as a catalyst.
What we could do as an improvement for our experiment is to use
Some kind of pump that will constantly pump oxygen into our
Fermenter, ideal equipment that does this could be a fish pump
That they use in fish tanks.
- Thermometer: - Again, in the scientific industry they have a thermometer
Equipped with their fermenter, this is so that they are obviously
Able to identify the temperature of the solution and this is
Helpful because if the temperatures reached too high it would
Kill off the yeast culture and if the temperature was too low it
Would slow down the reaction in the fermenter, so they will
Then be able to adjust the temperatures of the fermenter to
The best temperatures that the yeast culture will respire.
For us to improve our experiment we could also then add a
Thermometer to our fermenter so that us to will be able to
Identify if the temperatures are too high or low, we will then
Be able to change the temperatures to something more suitable.
- Gas Exit: - Lastly, in the scientific industry they have a gas exit fitted onto their
Fermenter and this is to allow the carbon dioxide to release and not
kill the yeast culture, in my experiment we pierced holes on the foil to allow the carbon dioxide to pass through, but it would be better to pump oxygen into the tank daily and then the oxygen will hopefully do the job of pushing the carbon dioxide out the beaker.
Apart from the improvements above more can be done to come out with more accurate and better results.
In this experiment no agitation was done onto the yeast cells, in order to improve my results and make them more accurate what I could do is agitate them, this way the agitation will then act as a catalyst because it is enhancing the fermentation process. What could also do is keep the temperature constant, it wouldn’t be a good idea to increase the temperature one day then the next day we will decrease it, this will just leave you with errors in your results and your experiment will turn out wrong. We could also have a device that is capable of removing the toxics from the solution due to the fact that they will kill the yeast cells in a matter of days, I don’t know of any equipment that is capable of doing this so I will leave this one out.
Evaluation:
Firstly, I will say that the method that I used for this experiment was a particularly good one and wasn’t really bad, but it could be improved in many ways which would’ve helped us to get more better and accurate results.
Also the results that I got were correct, and because of the research that I done on fermentation I knew that I was expecting this, I ensured that they were accurate by going up onto the internet and studying more about fermentation and the processing of it and what they use fermentation for, and I discovered that it is normal for the solution to become cloudy within a few days of the fermentation, it was also normal for the solution to let off the strong smell of alcohol.
When doing the experiment there were anomalous results, the reason for this was because I didn’t provide my yeast population with any oxygen and this then caused the yeast cells to die more quickly because they don’t have much oxygen to respire, another reason I came up with anomalous results was because I didn’t bother to agitate the solution because we didn’t have any equipment that was capable of doing this, the agitation helps the yeast cells to move about and this way they are capable of gathering oxygen. My results came out slightly incorrect because the growth of the yeast population was slightly wrong, this was because the yeast cells were not provided with the right factors that yeast cells need in order to perform fermentation.
A way in improving my investigation could be by looking up information about fermentation on the internet and look deep into how the yeast cells exactly work when they are fermenting, I could’ve also tried changing my method or just use different methods, this would help me to identify which method gives me the most accurate and best results out of all the methods. I could extend my investigation by investigating the way yeast cells work and what yeast cells are used for and how they are used in the industry, laboratory and other places.
