Osmosis is the net movement of solvent molecules (usually water) through a semi-permeable membrane from a region of high water potential to a region of lower water potential. Calculating the rate of osmosis is crucial in biology and chemistry experiments, such as observing potato tissue in different sucrose concentrations.
The Rate of Osmosis Formula
In a laboratory setting, the rate of osmosis is typically measured by the change in mass or volume over a specific period. The formula used in this calculator is:
Rate = (Final Mass – Initial Mass) / Time
A positive result indicates endosmosis (water entering the substance), while a negative result indicates exosmosis (water leaving the substance).
Factors That Affect the Rate
Concentration Gradient: The greater the difference in solute concentration between the two sides, the faster the rate of osmosis.
Temperature: Higher temperatures increase the kinetic energy of molecules, speeding up the movement across the membrane.
Surface Area: A larger surface area of the semi-permeable membrane allows more water molecules to pass through simultaneously.
Water Potential: Water moves from high water potential (dilute solution) to low water potential (concentrated solution).
Practical Example
Imagine a biology experiment where a potato cylinder is placed in distilled water: