Osmosis Eggsperiment

Osmosis Eggsperiment

Introduction

Clinton (2012) defines osmosis as “the movement of water from a region of high solute concentration to a low solute concentration through a semi-permeable membrane.” The concentration of an area depends on the solute present, a highly concentrated area having more solutes than a low concentrated area. The movement of water will continue until both sides of the semi-permeable membrane are of similar concentration (Solomon et al.,2019).

Water will only move across a semi-permeable membrane when there is a difference in concentrations; a term referred to as tonicity. Particularly in a cell, when the concentration outside is lower than the concentration in the cell or cytosol, then the solution is referred to as being hypotonic in relation to the cell (Raghunathan & Aluru, 2006). In this case, water will always move from into the cytosol until there is an equilibrium. However, when the molecules outside are higher than the concentration in the cell, then the solution is hypertonic, and water will always move out of the cell until there is an equilibrium. There is also an instance where the solute concentration of both sides of the semi-permeable membrane are equal, a situation where the solution is said to be isotonic in relation to the cell (Raghunathan & Aluru, 2006). Since there is equal concentration, there movement of water in and out of the cell is at similar rates and thus no net flow of water. (Raghunathan & Aluru, 2006).

The semi-permeable membrane is also referred to as a selectively permeable, that is, only some substances can be allowed to pass through and not others. The semi-permeability is made possible by the proteins at the surface, known as the peripheral proteins. They form carbohydrate chains act as antennae for communication (Society, 2012).

Osmosis is a vital process in biology, specifically in plants. One of its main functionalities is to stabilize the internal environment of an organism, by maintaining a balance of the intercellular fluids level, most importantly, water. It assists in the absorption of water and minerals from the soil since water will move in when the concentration is high within the root systems. Also, it maintains turgidity or shape of the plant cell and even in the movement of water between cells. In this paper, an experiment will be conducted to test the process of osmosis.

Hypothesis

The experiment tests the hypothesis that syrup is a hypertonic solution to the egg, and thus osmotic pressure will force water out of the egg. When placed in distilled water, which has a lower solute concentration, causes the liquid to enter the eggs’ membrane.

Materials and Methods

For the experiment to be successful, the following materials are required.

• Two fresh eggs in their shells
• 2 cups of water
• a graduated cylinder
• Two large cups
• One small cup
• white vinegar
• Karo syrup
• tap water
• pencil and paper
• apron
• safety glasses
• press and seal
• masking tape
• baking sheet
• tongs
• scales
• osmosis lab sheet

Figure 1: Osmosis experiment setup

Methods and Procedures

The experiment will take place in a lab, for four consecutive days, and on each day, the measurements of the egg will be collected.  On the first day, the mass of both eggs (with their shell) will be recorded. Using the graduated cylinder, measure 2 cups of vinegar in one of the cups. Label the cup as “Vinegar”. Place the two fresh eggs in the vinegar cup, and if necessary, cover it with a cup. After 24 hours, remove the shell.

On the second day, take the paper and pencil and record the observation on the eggs after being in the vinegar solution for 24 hours. Take the eggs out of vinegar, rinse them with water. Ensure that the cups that had previously been used with vinegar are cleaned for a syrup solution, and label them as syrup solution. Record the mass of both eggs in the paper. Then, place the eggs again in the syrup, cover them with the cup for another 24 hours.

On the third day, observe and record what has happened to the egg in the syrup solution. Remove and use clean water to rinse the eggs from the syrup solution. Before placing them in the distilled water for another 24 hours, clean the eggs. Then, put the eggs in distilled water, label the cups and let them stay there for another 24 hours.

On the fourth and last day, remove the eggs from distilled water. Clean then eggs and carefully record any observations, including the mass.

Results

After the experiment has been conducted, the results were recorded as below.

Table 1: Egg 1 data

Table 2: Egg 2 data

According to the results, it is evident that the mass and size of the egg increased when it was left in the white vinegar solution and tap water solution. However, when it was placed in syrup, then the size and mass decreased.  The information displayed in the table above can be displayed graphically below

Discussion

The data collected in the experiment revealed that osmosis was taking place. The mass and size of the egg changed differently when placed in different solutions. When it was in the syrup for 24 hours, the mass of the egg changed from 113.5 grams to 61.0 grams (egg 1) and 89.1 grams to 53.1 grams (for egg 2). Therefore, generally, the mass and size decreased, suggesting that water moved from the egg to the syrup solution. Thus, the syrup has a high solute concentration that egg, and therefore a hypertonic solution. The semi-permeability of the egg’s membrane allowed only water to move out of the egg to the syrup solution until an equilibrium of concentration was attained. The volume of the syrup in the liquid, therefore, increased due to the water from the egg. Also, due to the smaller molecules of water, it travelled more quickly into the cell than the syrup.

After the egg had been taken out of the syrup, it was placed in the distilled water. The mass of the egg changed from 61.0 grams to 100.3 grams (for egg 1) and 53.1 grams to 110.2 grams, increasing in mass and size; thus water moved into the egg. The movement of the egg continued until equilibrium in concentration was reached. Therefore, we can conclude that the distilled water was a hypotonic solution. Since the egg was from the syrup, it has lost water. When placed in distilled water, it absorbed more water, and thus water was moving into the egg.

Experimental error

Although vinegar solution was used and recorded a decreased mass and size of the egg, its primary purpose in the study was to remove the shell of the egg. However, it can still contribute to the loss of water through osmosis because the size of the egg increased from 75.6 grams to 113.5 grams in egg one and from 62.7 grams to 89.1 grams in egg 2. Therefore, this can skew the result since it contributes to experimental error.

Another error comes from the incorrect measurements of the eggs’ mass. Always limited by the accuracy of the measuring instrument, the recording of wrong measurements can lead to wrong findings and conclusion of the experiment. Furthermore, incorrect handling of the egg can lead to breakage and therefore introduce a crack on the egg. The crack can, therefore, allow water or liquid molecules to flow across in a non-osmotic process. Therefore, to eliminate or minimize such error, the egg should be handled with care, and measuring instruments with a high level of accuracy should be used to get accurate data.

Improvement of the experiment

One of the ways to improve on the experiment is to do away with the vinegar. Other methods of removing the egg’s shell should be used so that it does not interfere with the concentration of the osmosis process. Also, there should be at least three eggs, and the average mass gain can be calculated to eliminate any random effects that cannot be controlled in the experiment.

Conclusion

The hypothesis stated earlier was confirmed. When the egg was in the syrup solution, its mass significantly decreased. Therefore, it suggests that the concentration in the interior of the egg was lower than the concentration of the surrounding environment, the syrup. Due to the difference, water was forced to move from within the egg to the syrup through the process of osmosis.

However, when the egg was placed in distilled water, its mass and size significantly increased. It is therefore evident that the interior of the egg has a higher solute concentration than the surrounding environment of water. As a result, water moved into the egg, increasing its mass and size. Compared to the interior of the egg, distilled water is a hypotonic solution and syrup is a hypertonic solution.

References

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Clinton, Romelia. (2012). Biological Processes. White Word Publications.

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Raghunathan, A. V., & Aluru, N. R. (July 01, 2006). Molecular Understanding of Osmosis in Semipermeable Membranes. Physical Review Letters, 97, 2.)

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Society, F. (2012). Osmotic pressure. a general discussion. Place of publication not identified: Hardpress Publishing.

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Solomon, E. P., Martin, C. E., Martin, D. W., & Berg, L. R. (2019). Biology. Boston, MA, USA: Cengage Learning

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