# Rate of Osmosis - Concentration

Topics: Concentration, Osmosis, Solution Pages: 2 (436 words) Published: May 27, 2013
Rate of Osmosis Investigation
Lab Title:

Abstract:
Write this section last! It is a brief paragraph or 2 which outlines the purpose, the method, the pattern of results and the conclusion you reached. It is an overall snapshot of the whole investigation.

Introduction:
Purpose:

Biological Background: All living organisms are made of cells which are surrounded by a membrane. The cell membrane has many functions but the major function is regulating the passage of materials going in and coming out of the cell. These materials consist of sugars, salts, water and dissolved gases. Most materials move by simple diffusion from high concentration to low concentration. Some substances may be actively transported, which requires energy. The diffusion of water across a semi-permeable membrane is called osmosis. Osmosis is the net movement of molecules through a semi-permeable [1] membrane from an area of low solute concentration to an area with a high solute concentration. In this investigation, we are testing how concentration effects the rate of osmosis Hypothesis:

The more hypertonic potato pieces are to a saline solution, the more weight the potato will gain. However, the potato pieces will decrease in weight when they are placed in a hypotonic solution.

Dependent variables:
Change in mass of pieces of potatoes.

Independent variables:
solutions sucrose concentrations.

Controlled variables:
amount of time in the solutions
surface area of the potato segments

Factors held constant:
Identify and follow with a prediction/s about the results expected to either support or not support the hypothesis Materials and method
Materials:
2 large potatoes
Spoon
Ruler
3 x 250 mL beakers Knife
Paper towel
NaCl solution (1% and 10%)
Electronic balance
Distilled water

Method
1.Peel the potatoes and cut into 2cm3 cubes
2.Label the cubes...