Method.
- I will measure 200ml of each liquid solution in separate beakers.
- I will then label each beaker with the 0%, 1%, 2%, 3%, 4%, and 5%.
- Then I will measure each potato chip before adding two to each beaker and I will make a note of this I will make a presumption that the potato chip that was heaviest before will be the heaviest afterwards.
- I will then add two weighed potato chips to each of the beakers.
- I will then leave them all in the same room for approximately 24hrs.
- After the 24hrs I will take each potato chip out and make a note of each of the weights with the before weights.
- Finally I will throw all my used potato chips in the bin and wash and dry all my equipment and put it away.
I am going to use 5 different water percentages and 1 pure water solution. To make my test fair I will leave the skin on all the potatoes, I will leave them all in the same room so temperature will not affect the practical, I will make sure the beakers are all the same sizes so the surface area of the beakers will not affect the practical, by using the borer this will ensure that the potato chips are all around the same size and weight, I will also ensure the volume of liquid in all the solutions are the same as the pure water this will be 200ml and the one variable that I will change will be the strength of the salt solution. I will make my results reliable by using two potato chips for each liquid solution and taking an average of the difference weight for before and after. I will make sure my results are predictable by doing a prediction first I will then do a preliminary test and I will get my teacher to check this out and if this is correct then I know that my results need to follow a similar pattern to my preliminary results.
Osmosis can sometimes be known as diffusion. Diffusion occurs when two different liquids or gases mix together so that the concentrations of the two gases or liquids eventually become the same throughout this doesn’t happen in solids.
In solids the particles are very close together I want to find out if soaking potatoes in liquids can alter the particles and let salt particles pass through the potato and cause the potato to gain weight this is why I chose my method.
In this practical there are not many hazards you just have to be careful with the borer don’t hold the potato in your hand as it is likely that you will go through onto your hand and when using water and glass beakers you have to make sure that they don’t slip out of your hands.
I predict that the higher the salt solution the less weight gained.
This is my predictive graph as you can see the graph shows that the higher the salt concentration the lower the weight gained.
Preliminary work.
I will do a trial run of my experiment so I am clear how I am to do my experiment and also it is something to compare my real test with to make sure I do it correctly. In my preliminary work I will use one potato chip for each test.
These are my results:
This is a graph of my preliminary results I happy with my results as they have turned out how I expected therefore I will use these results in my work, this should make my results more reliable.
These are my results from my experiment:
Whilst doing the practical I didn’t have any problems this hopefully makes my results reliable. To improve my method I could of done 4 tests and took an average from 4 results rather than 3. This would of made my results much stronger. I could of also made my potato chips all exactly the same weight. I think that my results are very reliable and I would hope to get a similar set of results if I did the test again as I did them 3 times that includes my preliminary results. I am certain about my conclusion as I think my evidence ties in with the scientific facts that make me think that my results are reliable. To extend my understanding of the topic I could do further tests substituting the salt for sugar or I could do another test I could use gases or liquids instead of solid and liquids.
For example diffusion in gases can be demonstrated by taking two jars of gas, one containing oxygen and the other bromine a brownish gas.
