Preliminary Results
Apparatus
The apparatus I shall be using in this experiment are as followed;
- 5 Test tubes (to hold the sucrose and potatoes)
- Distilled water (to use with the sucrose for different Molars.)
- 5 potato cylinders that are equal in length (What gets reacted with the different molars.)
- Safety goggles (For safety in experiment and to protect eyes.)
- Sugar / Sucrose Solution (To investigate the effect of Osmosis.)
- Distilled water holder (To hold distilled water.)
- Test tube holder (To hold multiple test tubes.)
- Weighing machine (To weigh the mass of the potatoes.)
- Potato cylinder shaper
- Stop clock (To time the reaction.)
Prediction
I predict that in this experiment, the potatoes in 0M – 0.5M will have an increase in mass change, while the potatoes in 0.5M – 1M will have a decrease in mass change. I think this because I believe you need a certain amount of sucrose if you are going to get a decrease in mass change.
Fair Testing & Safety
In this experiment, safety is very important as I am dealing with potentially dangerous chemicals such as Sucrose. To protect myself and make the working atmosphere safe, I shall do the following things;
- Wear safety goggles to protect my eyes from unwanted stuff.
- Handle the sucrose carefully and slowly.
- Measure the end results carefully.
Fair Testing is also very important in this experiment; I shall do the following to make the experiment and testing fair;
- Keep all the potatoes the same length at the beginning
- Keep the varying Molars accurate
- Reset the mass scale each time a new potato is weighed
- Use the same distilled water
- Use the same sucrose
- Use the same type of potato.
Method
First of all, I shall get 5 test tubes and put them in 1 test tube holder. After that is done I will put varying concentration of sucrose in each test tube going from 0M to 1M. I shall get the varying molars by mixing the sucrose with distilled water. After this, I shall get 5 cylindrical potatoes and cut them into equal lengths of 4cm. Once I have done this, I will measure each potato and make sure their mass seems right. Next, I will drop each potato into each potato at the same time exactly and then start the stop clock for 25 minutes. Now I wait. Once the 25 minutes is up, I take each potato out the test tube and measure its new mass. I then record the results and repeat the experiment 2 more times, so I have 3 sets of results, I then find the average and draw the graph.
Results
Key: NM = New mass
% = % change
B = Mass before
Analysis
The patterns shown on my graph are that as the Molar increased, the percentage change decreased. This shows that in the higher molars, the pieces of potatoes got lighter more quickly because Osmosis had occurred. The best fit line on my graph proves the investigation of Osmosis. Also, as the molar decreased the percentage change increased as Osmosis had occurred less as there was less concentration.
My prediction saying that ‘the potatoes in 0M - 0.5M will have a positive mass change and that the potatoes in 0.5M – 1M will have a negative mass change was slightly right except after looking at my graph, I found that the exact point where the percentage change went from positive to negative or vice versa was at 0.625M.
Overall, I think my experiment went quite well, but I think that if I left the potatoes in the different molars for longer (like 30 minutes, not 25 minutes) then I would have gotten better, more accurate results.
Evaluation
After evaluating all of my evidence, I believe that overall, my experiment went according to plan. One of the things that were slightly wrong was my prediction as I thought that the percentage change would go from positive to negative or vice versa pretty much at 0.5M, but it didn’t. My Method went perfectly according to plan as I did exactly everything I mentioned. One of the main problems in the evidence I got, was that I only did the experiment for 25 minutes instead of 30minutes as I kept running behind schedule. When it comes to my fair testing, that went overall according to plan, except that not all the potatoes were exactly 4cm, as some were 3.9cm and others were 4.1cm. The reason this happened is because it was extremely difficult to measure the cylindrical potatoes and get them exact. Overall I believe my experiment went according to plan and I also believe my evidence and results were good.
When it comes to things I could improve, I could repeat each experiment 3 times again but for 30 minutes and see if my results would be any different. Also I could try as hard as I can to get every potato piece at 4.00cm on the dot.
Conclusion
In conclusion of this experiment, I have learnt a lot of background information on Osmosis and I have also learnt that Osmosis can occur in potatoes as I hope my investigation has proven. The final thing I have learnt is that as the concentration of Sucrose increases, the percentage change of the mass of the potatoes decrease and vice versa.
Final Conclusion
In my final conclusion of Osmosis, I have learnt a great deal about Sucrose, potatoes and Osmosis.
