Science 9: Lab 3-3B Detecting Vitamin C in Multiple Fruit Drinks
Alana D. and Alina J.
Purpose:
To understand the effect of adding an iodine-starch solution to different fruit drinks to determine the amount of vitamin C within them. If there is an ampleness of vitamin C in the drink, the solution will spark a colour change.
Hypothesis:
If an iodine-starch solution is used to test for the presence of vitamin C when added to another solution, then a fruit drink will change to a different colour detecting the presence of vitamin C.
Independent variable: fruit drinks
Dependent variable: amount of vitamin C
Controlled variables: amount of iodine-starch solution (7 mLs)
size of the drops of juice
concentration of iodine-starch solution.
Materials:
1 Vitamin C Tablet
Mortar and Pestle
4 100 ml Beaker
2 Medicine Droppers
Iodine-Starch Solution
4 Samples of Beverages of your choice
Water
Stirring Rod
2 10 ml Graduated Cylinder
Procedure:
Part One.
1. Grind up the vitamin C tablet using a mortar and pestle.
2. Transfer the grindings to a 100 mL beaker. Use about 100 mL of water to wash the grindings out of the mortar and into the beaker.
3. With the graduated cylinder, measure 5 mLs of the iodine-starch solution into a test tube.
4. Use a clean medicine dropper to add some of your vitamin C solution to the iodine-starch solution. Keep adding until you see a definite change in colour. Note the colour change. This colour change indicates that the vitamin C solution has destroyed the iodine in the iodine-starch solution.
5. Do a similar test with water. Measure 5 mLs of the iodine-starch solution into a clean test tube. Using a second, clean medicine dropper, add water to the iodine-starch solution. Note what happens.
Part Two.
1. Pour 7 mLs each of the iodine-starch solution into six different test tubes.
2. With the medicine dropper, add drops of one fruit juice until the substance changes colour (if at all).
3. Repeat step 2 with the other fruit juices.
4. Clean up and put away the equipment.
Alana D. and Alina J.
Purpose:
To understand the effect of adding an iodine-starch solution to different fruit drinks to determine the amount of vitamin C within them. If there is an ampleness of vitamin C in the drink, the solution will spark a colour change.
Hypothesis:
If an iodine-starch solution is used to test for the presence of vitamin C when added to another solution, then a fruit drink will change to a different colour detecting the presence of vitamin C.
Independent variable: fruit drinks
Dependent variable: amount of vitamin C
Controlled variables: amount of iodine-starch solution (7 mLs)
size of the drops of juice
concentration of iodine-starch solution.
Materials:
1 Vitamin C Tablet
Mortar and Pestle
4 100 ml Beaker
2 Medicine Droppers
Iodine-Starch Solution
4 Samples of Beverages of your choice
Water
Stirring Rod
2 10 ml Graduated Cylinder
Procedure:
Part One.
1. Grind up the vitamin C tablet using a mortar and pestle.
2. Transfer the grindings to a 100 mL beaker. Use about 100 mL of water to wash the grindings out of the mortar and into the beaker.
3. With the graduated cylinder, measure 5 mLs of the iodine-starch solution into a test tube.
4. Use a clean medicine dropper to add some of your vitamin C solution to the iodine-starch solution. Keep adding until you see a definite change in colour. Note the colour change. This colour change indicates that the vitamin C solution has destroyed the iodine in the iodine-starch solution.
5. Do a similar test with water. Measure 5 mLs of the iodine-starch solution into a clean test tube. Using a second, clean medicine dropper, add water to the iodine-starch solution. Note what happens.
Part Two.
1. Pour 7 mLs each of the iodine-starch solution into six different test tubes.
2. With the medicine dropper, add drops of one fruit juice until the substance changes colour (if at all).
3. Repeat step 2 with the other fruit juices.
4. Clean up and put away the equipment.
Discussion Questions:
1. In our hypothesis, we stated that if an iodine-starch solution is used to test for the presence of vitamin C when added to another solution, then a fruit drink will change to a different colour detecting the presence of vitamin C. This hypothesis was correct. When the fruit juice drops were added to the iodine-starch solution, each juice turned a slightly different colour depending on the original colour of the juice (pink for powerade, orange for orange juice, etc.). Our background research for this experiment was Part One of the procedure. Here, we saw that the iodine-starch solution changed colour when the vitamin C tablet was supplemented. This led us to be able to explain the actual changes of colour in the fruit drinks.
2. In this experiment, we tested for vitamin C in fruit drinks. To do this, we added drops of fruit juice to test tubes filled with 7 mLs of an iodine-starch solution. 12 drops of the Minute Maid Tropical Orange juice were added before the colour change was complete; 20 drops for the Aquafina+ drink; 30 drops for the Nestea Ice Tea; and 18 drops for the Tropicana orange juice. All variables were considered, identified and controlled - we were carefully monitoring the amounts of iodide-starch solution, drops of fruit juice, and the size of these drops. Our independent variables were the fruit drinks; our dependent variable was the amount of vitamin C; and our controlled variables were the amount of iodine-starch solution, the size of the drops, and the concentrations of the solution.
3. Between each drink tested, there were definitely differences in the change, but there was one that was the most significant. Firstly, the tropical orange juice was the one with the most vitamin C. This can be determined because it took this juice the least amount of drops for the iodine-starch to turn completely clear; we only needed 12 drops of this juice. Secondly, there was the Aquafina+ and this one took a significantly larger amount of drops, but still managed to turn clear after 20. Thirdly was the orange juice: the iodine-starch turned clear with just 18 drops of this juice, ranking it number 2. Finally, the ice tea had the very least amount of vitamin C. It took 30 drops of the drink, and the change was barely noticeable. Overall we had very successful results and they were just as we had expected.
4. Overall, our experiment was valid. We made sure to keep all of our controls and variables under our control at all times. Something we would have liked to change was our variation in beverages: we chose both tropical orange and normal orange juice. We think these two drinks were too similar and we could have gotten better results if we had used a different drink. A possible source of error was that each time we took turns dropping in the juice, this lead us to the possibility of having different sized drops of juice put into the iodine-starch solution. If we were to test again, we would want to test a bigger variety of drinks.
Conclusion:
This experiment was very successful. We learned how to detect vitamin C in different fruit drinks and the science behind it. Mixing the iodine-starch solution and the fruit drinks demonstrated how much vitamin C the drink contained - we could see this by how quickly a colour change occurred, and how clear the liquid was afterwards.
Our hypothesis was correct, overall. If there is an ampleness of vitamin C in the drink, it will not take very many drops to turn the solution clear. If there is little vitamin C in the drink, it may take a large number of drops for the solution to change colour, or it may not change colour at all (if there is no vitamin C present). Even after 30 drops of the Nestea ice tea in the solution, no colour change was taking place. This shows us that there was no vitamin C present, and it would have been pointless to keep adding more drops.
1. In our hypothesis, we stated that if an iodine-starch solution is used to test for the presence of vitamin C when added to another solution, then a fruit drink will change to a different colour detecting the presence of vitamin C. This hypothesis was correct. When the fruit juice drops were added to the iodine-starch solution, each juice turned a slightly different colour depending on the original colour of the juice (pink for powerade, orange for orange juice, etc.). Our background research for this experiment was Part One of the procedure. Here, we saw that the iodine-starch solution changed colour when the vitamin C tablet was supplemented. This led us to be able to explain the actual changes of colour in the fruit drinks.
2. In this experiment, we tested for vitamin C in fruit drinks. To do this, we added drops of fruit juice to test tubes filled with 7 mLs of an iodine-starch solution. 12 drops of the Minute Maid Tropical Orange juice were added before the colour change was complete; 20 drops for the Aquafina+ drink; 30 drops for the Nestea Ice Tea; and 18 drops for the Tropicana orange juice. All variables were considered, identified and controlled - we were carefully monitoring the amounts of iodide-starch solution, drops of fruit juice, and the size of these drops. Our independent variables were the fruit drinks; our dependent variable was the amount of vitamin C; and our controlled variables were the amount of iodine-starch solution, the size of the drops, and the concentrations of the solution.
3. Between each drink tested, there were definitely differences in the change, but there was one that was the most significant. Firstly, the tropical orange juice was the one with the most vitamin C. This can be determined because it took this juice the least amount of drops for the iodine-starch to turn completely clear; we only needed 12 drops of this juice. Secondly, there was the Aquafina+ and this one took a significantly larger amount of drops, but still managed to turn clear after 20. Thirdly was the orange juice: the iodine-starch turned clear with just 18 drops of this juice, ranking it number 2. Finally, the ice tea had the very least amount of vitamin C. It took 30 drops of the drink, and the change was barely noticeable. Overall we had very successful results and they were just as we had expected.
4. Overall, our experiment was valid. We made sure to keep all of our controls and variables under our control at all times. Something we would have liked to change was our variation in beverages: we chose both tropical orange and normal orange juice. We think these two drinks were too similar and we could have gotten better results if we had used a different drink. A possible source of error was that each time we took turns dropping in the juice, this lead us to the possibility of having different sized drops of juice put into the iodine-starch solution. If we were to test again, we would want to test a bigger variety of drinks.
Conclusion:
This experiment was very successful. We learned how to detect vitamin C in different fruit drinks and the science behind it. Mixing the iodine-starch solution and the fruit drinks demonstrated how much vitamin C the drink contained - we could see this by how quickly a colour change occurred, and how clear the liquid was afterwards.
Our hypothesis was correct, overall. If there is an ampleness of vitamin C in the drink, it will not take very many drops to turn the solution clear. If there is little vitamin C in the drink, it may take a large number of drops for the solution to change colour, or it may not change colour at all (if there is no vitamin C present). Even after 30 drops of the Nestea ice tea in the solution, no colour change was taking place. This shows us that there was no vitamin C present, and it would have been pointless to keep adding more drops.
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