Vitamin C Lab

Monday and Tuesday in class, my partner and I conducted the Vitamin C Lab. When we got back into lab, there were four pipettes filled with our four juices to test for concentration, these being : Pear Nectar, Apple Juice, White Grapefruit Juice, and Golden Goodness V8 Juice. Two of our classmates had to prepare the standard solution for the rest of the class. In the last two pipettes, there was a starch solution, and iodine, which had to be covered by aluminum foil. To start the test, we took a test tube and dropped 20 drops of the standard solution, then three drops of starch. Next, we dropped single drops of the iodine into the tube, and kept counting the drops until it turned from clear to dark blue. We repeated this for three trials and for each of the test solutions. We knew that the dark blue indicated the end because this meant the reaction was over between all of the vitamin c and iodine. Now we have to do a lab report on the results of the different concentrations.
Here are some pictures from the lab:

here, the two tubes on the left have not had iodine added yet

Here is a similar, and even simpler lab on this concept:

http://www.life.illinois.edu/boast1/sciencelessons/vitaminc.htm