Diffusion and Osmosis

Krysten Barsobia

12-7-11

3rd Hour

Diffusion and Osmosis

In this lab we will observe the process of diffusion and osmosis and also learn the effect of solute concentration to water potential to living plant tissue.

Abstract

The lab shows how each solutions differ, having high and low concentrations. We see how diffusion and osmosis works. Water moves from higher to lower concentration. Higher concentrations lose water to lower concentrations.

Introduction

We all know that molecules are everywhere. They are just out there smashing into each other. But, how do they work ? Do they have a system of knowing where to be at the right time ? How are they being regulated ? All the “smashing” around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to lower concentration. Diffusion stops when dynamic equilibrium is achieved. Osmosis is a special type of diffusion. It is the waters diffusion through semi-permeable membranes from a region of high water potential (hypotonic solute) to a region of lower water potential (hypertonic solute). Water potential is the measure of which direction the water will flow. The important thing that is behind diffusion and osmosis is water potential. Water will always go from high to low. Water potential is affected by two things: pressure and the amount of solute. Adding solute decreases the water potential, while adding pressure increase water potential. Water at atmospheric temperature is zero. Pressure potential is mostly positive in living and negative in dead. Plamolysis is the shrinking away of a plant's cell because water diffuses' out of the cell to a hypertonic solution. We agree predict that diffusion never stops until equilibrium and net movement no longer happens. Not everything can pass through or diffuse through the membrane. Anything that has a high solute will get a lot of water, and that water potential is a big factor in all of this.

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