This raisin has lost water by osmosis.
Method
- Set up equipment.
- Put one raisin in each beaker. One with a weak solution, one with a strong solution.
- Measure the mass of the raisins every 5 minutes for 30 minutes.
- Record results in a table.
Equipment
2 beakers – to contain the raisins and the solutions.
Scales – to measure the raisins and the sugar’s mass.
Stopwatch – to measure the time taken.
Tweezers – to pick up the raisins.
I need to take the following safety precautions:
- Don’t use fingers to pick up raisins.
- Keep an eye on the beakers.
- Don’t run with experiments.
I will make it a fair test by putting the same amount of sugar solution in each beaker and the times recorded will be the same.
Results
First set of results
Second set of results
Third set of results
Analysis
Average mass:
0% - 1.3g
5% - 0.6g
10% - 0.3g
15% - 0.1g
20% - 0.1g
25% - 0.3
30% - 0.2g
What happened?...
0% - The raisins mostly gained quite a bit of weight as 1.3 grams being the average weight.
5% - The raisins mostly gained weight.
10% - Two of the raisins stayed the same but one lost weight.
15% - The raisins lost mass.
20% - The raisins lost more mass than before.
25% - They lost more mass.
30% - They lost less mass than the previous test.
The overall pattern was the raisins absorbed more water when there was sugar in it and they lost mass when there was a lot of sugar in the solutions.
In terms of osmosis the solution absorbed and the solution changed from a weak solution to a strong solution.
My results and prediction were similar because as I predicted. The raisin gained more mass in a weaker solution and lost mass in a stronger solution.
Evaluation
The method I planned wasn’t good but it wasn’t bad because I had to change it from every 5 minutes for 30 minutes, to after 10 minutes I weighed the raisin and went straight onto the next one. Everything else was accurate but I forgot to mention weighing the sugar.
My results were accurate, because the experiment was a fair test and all the measurements were correct. There were no anomalies.
I could have made this experiment better because I could have timed the experiment better to fit with the time I gave in my method.
The results are reliable enough to get this pattern every time, because I repeated the tests three times and it came out with the same pattern.
By Emma Howell
