I am also going to use the same balance to weigh my potato chips. This is because the measurements may slightly vary between different sets of scales.
Apparatus
6 boiling tubes
Boiling tube rack
Sticky labels
Ruler
Scalpel
Cutting tile
Weighing scales
Potato slicer
Filter paper
Pen/Pencil
A potato
A measuring tube
A stopwatch
Method
Firstly using the sticky labels and a pen/pencil label each of the six boiling tubes with the solution molars (0.0, 0.2, 0.4, 0.6, 0.8, 1.0). Now carefully using a measuring tube measure out 25ml’s of each solution and place each solution into the relevantly marked boiling tube. Now using a potato slicer cut a potato into chips. Select six potato chips of similar sizes and using a ruler a scalpel and a white tile cut each potato to the same size length and width. For this experiment all the potato chips were 4 cm’s in length and 1 cm in width.
PHOTO/DIAGRAM
Now In turn place each potato chip onto the weighing scales and record each of the chips starting weights. Keep the chips in order that you weighed them. Record the starting weight of each in a table like the one below. I have decided to use six different molars of solution, this is because with six different sets of results you can easily see and trends in the results. The range of molars chosen is between 0.2 and 1 molar of sugar I have chosen this because after 1 molar of sugar osmosis is not as effective.
Now place each potato chip in its relevant boiling tube. Start a stopwatch and wait for 10 minuets. In the 10 minuets take 6 sheets of filter paper and label them like you labelled the boiling tubes. As soon as the 10 minuets are up remove all the potato chips from their tubes and place them on the relevant pieces of filter paper. Now re weigh the potato chips and record their new weight in the chart in the highlighted column.
To work out the percentage increase or decrease in the chips weight you need to use the formula difference in weights/original amount x 100. Record the results of this equation in the last column. Repeat the whole experiment at least two more times to make sure the results you have are accurate.
Safety
To carry out the experiment safely you have to follow the following safety rules:
- Always clear your work area from any potential hazards.
- Use sharp equipment like scalpels with care
- Report spills of any solution quickly to a teacher
- If glass is broken at any time leave it and inform a teacher.
- Always act responsibly, and listen to your teachers.
Preliminary experiment
To check that the method is right you have to carry out a preliminary experiment. In The preliminary experiment we will see if there are any faults in the method before we take proper results to analyse. Below are results from my preliminary experiment.
After the preliminary experiment I have decided to change my plan, as the potato chips didn’t have enough time for osmosis to take place. I am going to change the time between weighing each potato chip from 10 minutes to 30 minutes. This will allow the potato time for osmosis to take place in the potato. I then repeated the experiment to check that the new method worked. My results were good and I have decided to use them as one of my final sets of results. They are in the results section under experiment 1.
Analyzing results
Results.
There are the results from my three experiments
Experiment 1
The red results show anomalies in the results.
Evaluation Evidence
Evaluation
From my results you can see that potato chips left in a higher solutions of sugar have lost weight and the potato chips in the lower sugar solution have gained weight. This is because of a type of diffusion called osmosis. Osmosis is the movement of water molecules across a permeable membrane. The water moves from a place of high water concentration (e.g. a solution of just water) to a place of lower water concentration (e.g. a high sugar solution). In this experiment the potato acts as the permeable membrane. The water moves from the potato chip or into the potato chip depending on how strong or weak the sugar solution is. Below is a diagram showing how the water molecules move from water to a strong sugar solution.
Osmosis takes place when water moves both ways threw a membrane. The
