Osmosis and Diffusion Lab Report

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Osmosisand Diffusion Lab Report

Cellshave kinetic energy stored in them, which in normal case scenariosresults into the collision of molecules on one another and hencegetting new trajectories (Garavito,Kooi &amp Neuzil, 2006).What is gotten out of this collision and movement is diffusion.Diffusion refers to the random locomotion of molecules from a regionof higher concentration to a region of lower concentration. Osmosisis a kind of diffusion, which entails the movement of water via amembrane that is selectively permeable from an area of high waterdegree to an area of lower water degree(She, Jin &amp Tang, 2012).Any living system has an active transport and the active transportaids in movement of particles such as ions against theirconcentration gradient. During this process, ATP facilitates thecross membrane movement of particles. In this experiment, there ismeasurement of diffusion of small molecules using the dialysis tubes(Friedrichsen, &amp Pallant, 2007). The choice of the tube isbecause they have permeable membrane and can even allow the passageof larger molecules though slowly. Dialysis refers to the movement ofa salute via a selective permeable membrane.

Ininstances where two solutions that are on have same concentration dueto the solute concentration and there is no net movement realized,thus isotonic. If two solutions are different in regards to theirconcentration as a result of the solute concentration, the one thathas more concentration is referred to as hypertonic while the onewith less solute degree is referred to as hypotonic(Tomažič &amp Vidic, 2012).


Thematerials that are used in the lab include dialysis tubing, which isone 30 cm strip, and it has to be presoaked, distilled water, IodinePotassium Iodide solution, glucose (15%) and starch solution (1%),250 mL beaker, glucose Testape and string.


  1. Get a the dialysis tubing that has been presoaked in distilled water

  2. Tightly tie one of the ends

  3. Open the other end of the tube and insert 15 mL of 15% glucose and the starch solution

  4. Tie one end of the bag leaving a small room for expansion

  5. Take note of the color of the solution within the bag

  6. Using the test for the presence of glucose in the glucose-starch solution

  7. Fill a 250 mL beaker with distilled water and approximately add 4 mL of Lugol’s solution (IKI) to the distilled water.

  8. Establish the availability of glucose in the solution

  9. Note the results that are obtained in a data table

  10. Enter the bag in the beaker of solution and allow it to stand for almost 30 minutes

  11. Take note of the final colors of that appear in the bag and the beaker. One more time, using the testape test the solutions for presence of glucose




Color of the solution initially

Color of the solution finally

Glucose presence-initially

Glucose Presence-Final


Glucose-starch solution


Midnight blue




Water and the indicator




Table1: Glucose Presence in beaker and bag solutions


Fromthe data that has been obtained from the experiment, it highlyaffirms that molecules can and cannot also diffuse across thepermeable membrane selectively. The color that was observed affirmsthat iodine Potassium Iodide had small particles that could allow itto go through the pores of the membrane given that the color movedfrom the beaker to the bag. Glucose and water moved out given thatwater has small particles that would easily move through themembrane. On testing the glucose with testape, it tested positive.


Itcan be deduced that net movement of water by diffusion into dialysistube was observed owing to the higher concentration of the solute(starch and glucose) within the bag. On the other hand, there was netmovement of glucose by diffusion out of the dialysis bag as a resultof higher concentration of glucose within the dialysis bag.


Friedrichsen,P. M., &amp Pallant, A. (2007). French Fries, Dialysis Tubing &ampComputer Models: Teaching Diffusion &amp Osmosis Through Inquiry &ampModeling.&nbspTheAmerican Biology Teacher,&nbsp69(2),e22-e27.

Garavito,A. M., Kooi, H., &amp Neuzil, C. E. (2006). Numerical modeling of along-term in situ chemical osmosis experiment in the Pierre Shale,South Dakota.&nbspAdvancesin water resources,&nbsp29(3),481-492.

She,Q., Jin, X., &amp Tang, C. Y. (2012). Osmotic power production fromsalinity gradient resource by pressure retarded osmosis: Effects ofoperating conditions and reverse solute diffusion.&nbspJournalof Membrane Science,&nbsp401,262-273.

Tomažič,I., &amp Vidic, T. (2012). Future science teachers’ understandingsof diffusion and osmosis concepts.&nbspJournalof Biological Education,&nbsp46(2),66-71.