Bio lab report osmosis

Aim:

1) To determine the effects of different salt concentration on the percentage of weight change in potato cubes
2) To determine the isotonic solution concentration for the potato

Hypothesis:

1) If the concentration of the salt solution is higher than the concentration in the potato cubes, the percentage of weight change in potato cubes will be higher (positive). If the concentration of the salt solution is the same as the concentration in the cell, there will be no net movement of water through osmosis therefore there will be no percentage of weight change in potato cubes
2) The osmolarity of salt within the potato cubes lie between 0.8% and 1.0%. Thus saying, solutions of salt ranging from 0.0%(distilled water) to 0.8% will be hypotonic while the salt solution ranging from 1.0% to 1.2% wil be hypertonic.

Independent variable: The concentration of salt solution

Dependent variable: Percentage of weight change in potato cubes

Fixed variable: - Size of potato cube - Temperature of the surrounding - Type of solution

Biological Background:

Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Osmosis can be made to do work. The osmotic pressure is defined to be the minimum pressure required to maintain an equilibrium, with no nett movement of solvent. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity. Osmosis, unlike diffusion, requires a force to work. This force is supplied by the solute's interaction with the membrane. Solute particles move randomly due to Brownian