This is now iodine test. Again, I will show you the test for three testitudes. I label my testitudes one, two, three. If you have more testitudes, you just label more testitudes. In the first test of two, as I am doing in all the tests, I will add negative control. My negative control is distant water. I will add the three ML this time to make the result more visible. This is water has no organic compounds and therefore this is my negative control. I know it is going to give me negative results. I am using it to compare my results to it. In the next test tube, I will add, I need a positive control and it is going to be a solution of starch. Starch solution is my positive control. So iodine is a test of starch. Not for any polysaccharide. It is a test for starch. As discussed per the lecture, iodine gives me dark blue color or dark purple color for a positive result, for the existence of starch. And yellow color, which is the original color of iodine in case of negative result. I will test for you the milk to check if milk contains starch or not. So in my third test tube, I have three ML of milk. You can test any solution that you want using the same procedure. So three ML of milk. I do not mix the dropper pi pads with each others and I add in each test tube four to five drops of iodine solution until the color is a key. Sometimes iodine solution is too light. We will need to add more. And sometimes it is good enough. OK, results are clear. This is the result of my negative control. This is the yellow color, original color of iodine. This is negative result. This is the color of my starch solution, dark purple or dark blue color. This is my positive control. And this is the result of the milk. As you can see, milk result is a closer to the negative control than it is to the positive control. And therefore, there are no starch inside the milk. This is the test and this is how you can test any solution for the presence of starch.