Diffusion and Osmosis Lab
Examining Diffusion and Osmosis
Introduction:
Purpose:
1. To simulate and observe the diffusion of solutes and the osmosis of water through a semipermeable membrane through color change and sugar tests. 2. To speculate osmosis occurring in dialysis bags and potato cores by comparing percentage change in masses.
Background information:
Molecules are always in random, constant movement due to their kinetic energy. This causes the molecules of a cell to move around and bump into each other.
The random movement of molecules from an area of high concentration to low is called diffusion.
Osmosis, a specific kind of diffusion with respect to water takes place in the cells. This kind of diffusion is where water moves through a selectively permeable membrane, that is, a membrane that only allows specific molecules to pass through. Diffusion and osmosis stops when a dynamic equilibrium is reached, that is, the concentration on both sides are equal to each other. To be noted, that at this point, molecules are still in constant motion and random movement; however, the rates at which molecules moving from one area to another are equal and there is no net movement occurring between the two areas.
If two solutions have reached this equilibrium state, they are said to be isotonic. If they differ, the solution with a higher concentration of solutes is hypertonic with respect to the other; the solution with lower concentration is hypotonic. Water potential describes the tendency of water moving to another area. Since solutions always tend to reach a state of equilibrium, water usually moves from a hypotonic solution to a hypertonic solution in order to dilute the higher concentration. Therefore, we say that hypotonic solutions have a lower solute concentration and a higher water potential.
The net movement of water in a plant cell can be described using the two terms, turgor pressure and plasmolysis. Turgor pressure refers to the pressure of water exerting against
Introduction:
Purpose:
1. To simulate and observe the diffusion of solutes and the osmosis of water through a semipermeable membrane through color change and sugar tests. 2. To speculate osmosis occurring in dialysis bags and potato cores by comparing percentage change in masses.
Background information:
Molecules are always in random, constant movement due to their kinetic energy. This causes the molecules of a cell to move around and bump into each other.
The random movement of molecules from an area of high concentration to low is called diffusion.
Osmosis, a specific kind of diffusion with respect to water takes place in the cells. This kind of diffusion is where water moves through a selectively permeable membrane, that is, a membrane that only allows specific molecules to pass through. Diffusion and osmosis stops when a dynamic equilibrium is reached, that is, the concentration on both sides are equal to each other. To be noted, that at this point, molecules are still in constant motion and random movement; however, the rates at which molecules moving from one area to another are equal and there is no net movement occurring between the two areas.
If two solutions have reached this equilibrium state, they are said to be isotonic. If they differ, the solution with a higher concentration of solutes is hypertonic with respect to the other; the solution with lower concentration is hypotonic. Water potential describes the tendency of water moving to another area. Since solutions always tend to reach a state of equilibrium, water usually moves from a hypotonic solution to a hypertonic solution in order to dilute the higher concentration. Therefore, we say that hypotonic solutions have a lower solute concentration and a higher water potential.
The net movement of water in a plant cell can be described using the two terms, turgor pressure and plasmolysis. Turgor pressure refers to the pressure of water exerting against