I need to carry out a experiment to find out the concentration of some urine samples. However, I am just provided with some simple apparatus (test tube,beaker........) I plan to measure the light penetration of the urine but I find out that it does not works because even the most yellowish urine is a clear solution but not cloudy. So, how can I measure the concentration of the urine qualitatively or semi-qualitatively (or even quantitatively) with just these simple apparatus? I am thinking of using Visking tubing? Will it works?