Osmosis Study

Abstract

In this experiment, we studied the effects of diffusion and osmosis in cellophane tubing using a sucrose solution at different temperatures. The parameters of this experiment would define which temperature would allow the greatest increase of absorbance of the 40% sucrose solution across the membrane of the tubing. After the experiment, the conclusion was drawn that the tubing at room temperature had the greatest increase of absorbance closely followed by the tubing in the ice solution and then the warm water tubing had the lowest absorbance.

Introduction

This experiment was done to have a more in depth understanding of osmosis and diffusion. It was important to understand this concept so our group decided to investigate the effects of diffusion. Diffusion is the spontaneous movement of particles from an area of high concentration to an area of low concentration. More specifically our experiment was set up to test diffusion in the dialysis tubing in a sucrose solution at three different temperatures. Our hypothesis stated that the tubing in the highest temperature would have the highest absorbance due to the fact that the molecules would be moving faster. We made that assumption because in cold water the water molecules would move slower thus creating less movement and less of a chance to move across the permeable membrane.

Materials and Methods

This experiment was very similar to the experiment that was done in class. We added the temperature as a variable and modified the method accordingly. The materials used were the dialysis tubing and 3 water baths. The water baths were at room temperature, containing ice, and warm water (78°C).  A 40% sucrose solution inside a dialysis tube was used for this experiment. We filled the tubing half way and used clamps to close the bag. We labeled each tubing and weighed before placing them in the bath. We used a balance to weigh the samples and a stopwatch to reweigh the samples at 0, 10, 20, and 30 minute intervals.  We tested 5 samples per condition for a total of 15. The data was measured in grams to the nearest tenth and we plotted the data in excel. The results will be shown in the results section.

Results

According to the experiment, the data shows that the room temperature water bath  samples had the greatest increase of absorbance across the permeable membrane of the tubing. This was somewhat unexpected because our hypothesis stated that it was assumed that the highest temperature water bath would have the highest absorbance. Instead it had the least and the bath that contained the ice had the second highest absorbance but not by that much as shown in the raw data below.

Figure 1. Raw data of the weights of the actual samples at the various temperatures.

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