Biology Osmosis Lab Report

1876 words 8 pages
Osmosis Lab Report


Evan Gerber
Claire Cambron

First Lab Report
Wednesday 10:30am
February 20, 2013
Theresa Gburek

The major objective of the experiment was to test the effect of the concentration gradient on the diffusion rate. It was hypothesized that the greater the stronger the concentration gradient, the faster the rate of diffusion would be. To test this, dialysis tubes were submerged in different concentration fructose solutions. We weighed the tubes at specific time intervals to measure the rate of diffusion of water in each different solution. The results illustrated that increased concentration gradient increases the rate of diffusion of water in the tubes. We concluded that as concentration of the
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The independent variable in the experiment was the concentration of the solution, and the dependent variable was the rate of diffusion.
Table 1: Time (min) | 0 | 5 | 10 | 15 | 20 | Mass (g) for 5% Solution | 19.48 | 19.42 | 19.08 | 18.89 | 18.59 | Mass (g) for 10% Solution | 19.35 | 18.95 | 18.49 | 17.91 | 17.60 | Mass (g) for 20% Solution | 21.65 | 19.95 | 18.59 | 17.55 | 17.08 |

Chart 1:

The results illustrated that increased concentration gradient changes water flow due to osmosis. In each trial, I found that the rate of diffusion was faster in solutions with higher concentration gradients (see Chart 1). It can be seen both in the table and chart that with each increase in solution concentration, there is a greater difference between the initial and final mass of the dialysis tubes (see Table and Chart). The rate of diffusion for the tube in the 5%, 10%, and 20% solutions respectively were 0.231 g/min, 0.454 g/min, and 1.154 g/min (see Chart 1). This is due to the solute molecules moving from an area of high concentration to an area of low concentration.

The actual results of the experiment agree with the expected results of all three hypotheses. Therefore, the results suggest that there is positive relationship between the concentration gradient of the solutes and their diffusion rate. The higher the gradient, the faster the diffusion rate. This is because the solute particles will move from an area of high concentration to an


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