How Temperature Affects Osmosis. By: Irfan Nadiadi Sarah Mugharbil Rhiannon Kemp Michael Reese. Hypothesis. The rate of Osmosis depends on the Kinetic Energy of the particles being diffused.
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).
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.
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.
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.
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.
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
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.
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.
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/