 So, we want to do a test now that indicates the presence of a polysaccharide called starch. And the indicator that we use for this is something called IKI, it's just an iodine compound. So, we're going to do the demonstration by putting in some water in one test tube, it's just plain water out of the tap, and then we're going to put some starch solution in the other test tube. Now, indicators work by showing a color change. So when I put two drops of the indicator in the water, you see that it stays the same amber color as the IKI solution. But when I put drops in the starch container, you see that we get a completely new color, now we have a dark blue or black color. And so IKI turns blue or black in the presence of starch.