I. An osmolarity measuring device for providing a semi-quantitative color measure of liquid's osmolarity, said device comprising: a. none or more coloring agents; b. none or more swelling agents; c. none or more solutions; d. a vesicle with a continuous integument, containing within said integument at least one of a group consisting of said coloring agent, said swelling agent and said solution; and e. a support of absorbent material impregnated in at least one area with a plurality of said vesicles; wherein the apparent color of said area alters if the osmolarity of said liquid is within a pre-determined range.