INTRODUCTION

Osmosis is the process in which water transports itself through a cell membrane, from a region with higher concentration of water to a region with lower concentration. This is done as the cell’s attempt to achieve equilibrium. This experiment aims to demonstrate how osmosis works, as well as the effects it has on cells in different environment. In this experiment, the potato will play the role of the cell, which will be put into solutions with different concentrations of water. Hence the independent variables of this experiment is the amount of salt in each solution. The dependent variables are the mass of the potato after being put in the solution, and the amount of water left in the beaker.

 

The hypothesis of this experiment is that the potato in the salt water solution will become salty because the salt content will be absorbed by the potato. The potato will also shrink because the water will be transported outside, hence the volume of water after the potato will increase. However, the potato in the fresh water will gain weight because the water from outside the potato will be transported inside the potato, hence the remaining water will decrease.

 

PROCEDURES

Materials that will be used during this experiment are of the following:

- 2 of 300 ml beakers

- a measuring spoon

- a mixing spoon

- a graduated cylinder

- a scale

- 2 of 4 g pieces of potato (cut in quarters)

- 400 ml of water

- and 2 tea spoons of salt

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Procedures of this experiment are of the following:

1. Cut the whole potato into quarters. Make sure all the pieces are equal in weight (4 grams)

2. Pour 200 ml of water in each beaker

3. Measure two tea spoons of salt and pour it in one of the beakers

4. Label the beakers with "salt water" and "fresh water" accordingly

5. Use a mixing spoon to mix the salt until it is fully dissolved

6. Place the two slices of potato in each beaker

7. Set the timer for 1 hour (60 minutes)

8. Wait for the time to elapse

9. Remove both potatoes from the beaker and weigh them on the scale, one by one

10. Pour the remaining water from each beaker into the graduated cyliner one by one and measure the volume

11. Record all the data obtained in the data table.

 

DATA TABLE

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Both beakers contained 200 ml of water before the experiment, with both 4 g pieces of potato. The first beaker was 0 teaspoons of salt, and the second beaker had 2 teaspoons of salt. After the experiment, the volume of water in the first beaker remained 200 ml. However, the water in the second beaker decreased by 22 ml. Both potatoes were 4 grams before the experiment. However the potato in beaker one decreased by 1 gram after the experiment, and the potato in beaker 2 decreased by 2 g after the experiment.

 

RESULT

In conclusion, this experiment was created to demonstrate the process of osmosis in different water concentration. Though this experiment demonstrated the transport of water across a membrane, it did not prove our hypothesis. In the hypothesis, it was predicted that the potato placed in the salt water solution would decrease in mass, where as the potato placed in the fresh water solution would increase. This statement was only partially proven, because although the potato in salt water lost some of its mass, so did the potato in the fresh water solution. The hypothesis also states that the volume of salt water would increase, and the volume of fresh water would decrease. This is not proven because the volume of salt water decreased by 22 ml. The volume of the fresh water also was not decreased, however remained the same. Furthermore, the experiment also demonstrated effects that were not anticipated in the hypothesis, such as change in texture of the potato. The potato placed in the fresh water became more solidified, where as the potato placed in salt water solution became softer and more yielding. Therefore, it can be concluded that this experiment only proves the hypothesis that states that the potato placed in the salt water solution will decrease its mass.