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How does the sugar level affect the rate of Fermentation?

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Science Coursework: Fermentation How does the sugar level affect the rate of Fermentation? Aim: The aim of this experiment is to find out whether the rate of Fermentation is affected by the amount of sugar. Apparatus: The equipment used is: * Bunsen burner. * Heat proof mat. * Boiling tube. * Delivery tube. * Water bath. * Water flask. * Thermometer. * Stop watch. * Yeast and Sugar. * Digital weighing scale. * Water. * Measuring cylinder. * Test tube. * Tripod Method: * Fill the water bath with water (not to the maximum). * Fill the boiling tube with 10ml of water. * Add 2g of yeast to the water and add sugar (1g, 2g, ...up to 5g). * Put the Boiling tube into the water bath. * Connect a delivery tube onto the boiling tube. * Fill a test tube with a reasonable amount of water. * Place the other end of the delivery tube into the test tube. * Put the Bunsen burner on a heatproof mat. * Place the water bath on the tripod and heat the water. * Measure the temperature of the water (in the water bath) with the thermometer. Stop the heating until it reaches 40�. ...read more.


I must make sure that the Fermentation lock is not damaged so that it allows the escape of CO2 gas without the entry of oxygen, which could oxidize the ethanol produced. All these procedures must be taken into account in order to produce precise and reliable evidence. The variables that can be changed are the amount of yeast, amount of sugar and the temperature of each reaction. The only variable that will change is the amount of sugar as it goes up by 1 gram each time. The temperature shall remain at 40� degrees and the amount of yeast will always be 2g. Safety precaution: The equipments used in this experiment are quite safe. However, care is needed in handling glassware, as they are easily broken. I will use a heat proof mat so that the table doesn't catch fire. Prediction: Theoretically, the higher the amount of sugar, the faster Fermentation should happen. The GCSE chemistry revision guide states that yeast contains an enzyme which converts sugar into Carbon dioxide and alcohol (ethanol). So, if we add more sugar, the yeast will have more to work on. In a brief summary, the more sugar added, the quicker Fermentation should happen. ...read more.


- Intoxication by ethanol, some yeast cells may be intoxicated and die. -The tubes have to be lifted out of the water bath to take measurements - the environmental temperature could have affected the rate of Fermentation every time measurements are taken. If a further investigation is to be carried out, the temperature of the environment and the types of the sugar used are the interesting fields to head forth towards. Ali Hammuda Background information about Fermentation: Fermentation is a biological process involving the breakdown of sugars by bacteria and yeast using a method of respiration without oxygen (anaerobic respiration). It involves a culture of yeast and a solution of sugar, producing ethanol and carbon dioxide with the aid of the enzymes. This process can be slowed down by denaturing of the enzymes at a certain temperature. As products, ethanol and carbon dioxide are produced, in form of liquid and gas respectively. The reaction follows this equation: Glucose solution + Yeast (zymase) Carbon dioxide + Ethanol + (Energy) C6 H12 O6 (aq) 2C2 H5 OH (aq) + 2CO2 (g) Fermentation is also used for bread-making. The reaction that occurs in bread making is exactly the same as that in brewing. When bread is put in the oven, the yeast is killed and the reaction stops. Ali Hammuda ...read more.

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