Prediciton
I predict that as I increase the concentration of glucose then the amount of water moving in or out the potato will change. Dilute glucose or distilled water will make the potato increase in length and mass. I can support this prediction by looking back at my introduction on osmosis. Water will move into the concentrated potato cells because of the high concentration gradient. In very concentrated glucose solution water will move out of the potato and into the glucose solution I predict that the length and mass of this potato will go down.
Safety:
I will make sure that my experiment is safe by wearing goggles where necessary and making sure that I do not spill any liquid.
Method:
I am going to use a size three-cork borer to cork a nice sized potato and then cut the corked pieces into four centimetres then they will be weighed. The weight will be recorded to two decimal places. Then I will measure out 20 ml of different sugar solutions and pour them into six different test tubes. The test tubes will be resting in a test tube rack. The range of sugar solutions starts at distilled water, 0.1 m, 0.2m, 0.3m 0.4m, and lastly 0.5m. The potato pieces will then be placed in the six test tubes and left for 24 hours. After 24 hours, the potato bits are weighed once more. The weight is measured to two decimal places as well and then recorded. This experiment will be repeated two times for each concentration of sugar solution.
Variables:
In this particular experiment, various variables could be changed.
- Concentration of solution
- Temperature of solution or Temperature of the room
- Amount of solution
Making my experiment fair:
I will make sure that the potato chips are the same size and mass. I will make sure that I will use the same size of boiling tubes and borer. In my case I have chosen to test the variable of concentration of solution. I decided to do this because it seemed the best variable to get good results and easier to manage. Using different amounts of concentration, a range of results can be achieved.
Range:
For the range of observations, I have decided to use the concentration. It ranges from distilled water to 0.5m.
Distilled Water, 0.1m, 0.2m, 0.3m, 0.4m, 0.5m
Using the range of concentration, it makes it very easy for me to record them. All that needs to be done, is the concentrations are put in a table with the weight along side.
Apparatus:
In this practical, the apparatus, which was used, included:
- A knife
- Glass Rod
- Cork Borer
- Six Test Tubes
- A Test Tube Rack
- Potatoes
- Potato pieces
- A Scale
- Six Different Concentrations of Sugar Solutions
My Results:
Recording the results of the weight after each experiment was very easy. There was little hassle involved. Therefore producing an accurately detailed result table.
Evaluation:
Although all the results were obtained, this experiment could have been more precise. The scales that were used were sometimes dirty, which could have added more weight than necessary. A better scale could be in order if the practical was repeated. Also, a scale that went to two or three decimal places would of made this practical more accurate. Another thing that could make this experiment more accurate would be some kind of device to cut the potato bits into the same lengths as each other. However, I must vouch that I tried my best to cut the potato as precisely as possible. One more thing would be a timer. In order to achieve the best results, the timing must be correct. It was slightly impossible for me to take all six-potato bits out at exactly thirty minutes. Thus, it left some potato pieces in longer than other giving them maximum exposure to greater osmosis. All in all, it was an adequately accurate practical. Fortunately, there were no anomalous results in this assessment.
