I am going to investigate the concentration of salt. I think that this is the easiest for me to do and I also think that I can get a good set of results from it.
My predication:
Osmosis is the passage of water from a region of high water concentration through a semi permeable membrane to a region of low water concentration. In this case, the holes in the membrane will allow the water molecules to pass through the solution and the potato. I think that the mass of the potato will increase when there is less salt in the solution.
Apparatus:
Method:
First I will prepare the pieces of potato so that they are all about the same size and weight. I will then take note of each amount and record what pierce weighed what. I will then put 3 pieces of potato in each of the different concentrations and I will leave it for a while so that osmosis will definitely take place. When I have left it for a while, I will take out the potatoes and weigh them all again and find out the different from the before and after weight. I will then take the average of the potatoes from each of the different concentrations.
Diagram:
Safety:
I will need to make sure that I carry out the experiment safely and efficiently. To do this I will make sure I:
- Will wear goggles to prevent anything from going in my eyes.
- Will use the knife with precaution and make sure that none is around me when I am using it.
- Keep the water off the surface and floor to prevent people from slipping.
- Will work in an area with space so that I don’t get in anyone’s way.
Results:
Concentration: 0
Concentration :0. 5
Concentration: 1
Concentration 1.5
Concentration: 2
Obtaining Evidence
From these tables you can see that the greater the concentration, the more the mass changes. I.e. the more the mass decreases. You can also see that the average change in mass decreases as the concentration increases.
Analysis:
See the graph for this please.
Conclusion
You can see from my results that there isn’t one result that looks out of place. You can also see that the masses of the potato chips before the experiment are all quite close together and this is good because it made the experiment much more fairer and enabled me to get more accurate results.
The graphs and the results show that:
- Osmosis actually took place in the experiment.
- As the concentration increased, the percentage of the weight difference decreased with it.
Evaluation:
I think that the investigation was good because I got good accurate results and I think that this is due to the fact that I did actually make the experiment a fair test. To make this experiment better, I believe that I could have done one test at a time so that I could have concentrated on one at a time to make it fairer and even more accurate. I could have also been more organised in my group so that I would have concentrated more, therefore have gotten better and fairer results.
Overall though, I think that I did the experiment well and I think that I got good and accurate results.
Jake Gallop
CW Draft
