By: Irfan Nadiadi Sarah Mugharbil Rhiannon Kemp Michael Reese

Hypothesis The rate of Osmosis depends on the Kinetic Energy of the particles being diffused. Because energy is directly related to heat, temperature governs the amount of kinetic energy the particles have. As temperature increases or decreases, the rate of Osmosis should also increase or decrease, causing the potato cores to lose mass faster or slower

Procedure Step 1: Determine what environments the experiment will take place in. We were restricted to only using four environments at -62.2° C (freezing), -15.5° C (cold), 20.9° C (room temp.), and 95.5° C (boiling).

Procedure Step 2: Mix 5% Salt Solutions and add a consistent amount to each beaker. Then cut, weigh, and record four potato cores. We then added 25ml of Salt solution to each beaker.

Procedure Step 4: Record the temperature of each environment you are testing in and keep the solution (without the potato cores) in the environment for 5 minutes. This ensures the temperature will not be changing from room temperature when you add the potatoes.

Procedure Step 5: Add the potato cores to the salt solutions, checking and recording the mass of the cores at consistent time intervals. Once adding our cores, we checked the mass every 10 minutes for 50 minutes.

Data Time [min] Freezer Mass: -62.2° C [g] Fridge Mass: -15.5° C [g] Room Temp Mass: 20.9° C [g] Boiling Mass: 95.5° C [g] Average Mass Change Per 10 Min: 0.092g0.158g0.412g0.065g

Analysis When we plotted the data points and fit equations to the graph, we found the equations were sinusoidal because the potato cores continued to lose and gain water over time. Equations: -62.2° C: -15.5° C: 20.9° C:

Analysis

The sine functions on the previous slide are a good example of how temperature affects osmosis. The period for the function for room temperature (20.9° C) is much shorter than that of the function for freezing (-62.2° C). This represents the rate of Osmosis because over time the potato cores will continue to gain and lose water

Observations As hypothesized, the average rate of Osmosis decreased significantly when put in freezing conditions; water was absorbed and released slowly and in small quantities. When the temperature was higher, water was absorbed and released much faster and in higher quantities. This can be described by how temperature is affecting the kinetic energy of the water molecules in the potato.

Observations In warmer temperatures, the higher kinetic energy causes water particles in the potato to move faster. Due to the second law of thermodynamics, these particles will tend to diffuse from high to low concentration, thus trying to dilute the salt concentration in the solution outside.

Observations Although we found the rate of Osmosis to increase as temperature increases, when we put the potato cores in boiling water, the kinetic energy was so high that the water had reached its molar heat of vaporization, and quickly evaporated before the particles could completely diffuse. The high temperatures also damaged the Aquaporin’s in the potato cell membranes, stopping the regulation of the flow of water. For these reasons, we didn’t include the boiling water environment in our experiment/

Conclusion The purpose of this lab was to see how temperature would affect the rate of osmosis. The results of this lab were that for the freezer we had a average change of 0.092(g) for every 10 min, for the fridge we had 0.158(g), for the room temp. We had 0.412(g), and for boiling we had 0.065(g).

Conclusion The experiment had a few potential errors. For the boiling environment, although the aquaporin’s were damaged, most of the water evaporated, leaving less water to diffuse. This affected our data significantly so we decided to omit the information for the boiling environment. Another issue that may have affected the mass measurements was how the potato skins were peeling in the water. Our mass measurements may have been lower than what they could have been.

Conclusion: Changes If we were to do this experiment again, it would be better to test the hypothesis in multiple environments such that information wouldn’t have to be extrapolated to make a prediction, but rather have a test subject in a range of different temperatures to provide accurate results.

Conclusion: What we learned We learned for this lab that temperature does affect the rate of osmosis. It is hard to have a specific picture of how much it affects it with this lab but based on the results we have gathered we can tell it does affect it. What we saw with boiling was that it gains mass instead of losing it. The temperature that the rate was fastest was in fact room temperature at a change of ____%. This relates to how cell maintain homeostasis within our body.