The purpose of the lab is to discover the osmolarity of the potato tissue.
Osmolarity is a concept similar to concentration, except it is the total number of solute particles per liter. In this lab we can show osmolarity by using sucrose solutions and potato ores. This experiment displays hypertonic, hypotonic and isotonic solutions. A hypertonic solution is a solution with a relatively higher concentration, hypotonic cis relatively lower, and isotonic is the same.
Constant = size of potato core
Independent = sucrose molarity
Dependent = mass percentage change
Follow lab safety protocol and be careful with cork borer.
1. With a cork borer, cut six cores from a potato. The cores should all be as close to the same length as possible: 30-50 mm cores are recommended. 2. Before continuing, produce a table that will show the volume and mass of the potato cores before and after being placed in solutions of 6 different sucrose molarities. 3. Determine mass of potato cores using a laboratory balance. Record in table. 4. Place each core in a different test tube labelled with the core’s identification letter and the molarity of the sucrose solution to be placed in the tube 5. Add a labelled molar solution to each test tube until core is covered. Place foil over each tube and store for 24 hours 6. On the next day, repeat step 3
The osmolarity of the potato core is 0.4 M, I determined this by finding where on my graph the percentage change in mass was equivalent to 0. This meant that there was no change in mass, the tissue and solution were isotonic, and the molarity of the solution is the same as the osmolarity of the tissue. In this lab, and all experiments, an accurate measurement of mass was crucial to finding the correct results, trend, and osmolarity. The conclusion of this lab was based off of a negative trend on the graph which could have been skewed from inaccurate data.
In order to attain more reliable data I could have done multiple trials in the procedure which would clarify my results and conclusions. Also to generate better data a more precise device for measuring the mass of the potato cores could have been used. Also the size of the potato cores could have been more constant to create more accurate data. Outside of this experiment osmolarity is used in urine tests to calculate the concentration of certain particles in urine. An osmolality test can also be used for the blood to see the number of solutes present. These tests are then helpful in diagnosing and treating patients.