Hypertonic solution: Higher solute concentration outside the membrane
Hypotonic solution: Lower solute concentration outside the membrane
Isotonic solution: Equal concentration of solute inside and outside the membrane.
Things to remember:
A potato is a plant and a root. It is very high in sugar content because roots store sugar in the form of starch. There is also some water. Plant cells have cell walls which keeps them structured.
Water moves from high to low concentration across cell membranes.
When the potato was placed in hypotonic solutions, this means that the potato was immersed in solutions that had a LOWER concentration outside the membrane. The water should move INTO the potato and make it swell. Swollen potatoes are hard and crisp.
Conversely, when the potato is placed in hypertonic solutions, it was put into solutions that have a HIGHER concentration outside the membrane. The water inside the potato will move OUT of the potato and make it shrink. Shrunken potatoes are flimsy.
When the potato is placed into isotonic solutions, this means that the water will move into and out of the potato at the same rate and there will be no structural change.
Your task is to determine which of the solutions would be considered hypertonic, hypotonic, and isotonic. Your analysis should include a description of each and the effects of each on the potato.
Your hypothesis is to determine the range of tonicity. In other words, make a prediction on which range of solutions would be considered hypotonic, which is isotonic, and which is hypertonic based on the change in your potatoes. Work backwards from this and determine an acceptable problem statement. The introduction should talk about osmosis and why it is important.
Your table and graph should be done in Excel. Your table is Table 1 and your graph is Figure 1. The graph should have a self-explanatory title. It should also include a line of best fit and the equation for the line of best fit. Use the equation to make predictions for solutions of 1.5M and 2M.
So you have an idea of how to write up your lab, I have provided an example for you to reference. You must include it in your bibliography. Do not plagiarize this lab report, as it does not follow the IB format. Use it as a guide. Here is a model of an SL bio lab report on osmolarity. Do not plagiarize this report, but you may use it as a reference.
This is a physics forum that focuses on potato osmolarity. Use it as a reference.
The rough draft for the potato lab is due March 5. Final paper is due March 19.