The graph shows a inverse proportional relationship between the time and the number of drops required to decolourise the DCPIP solution: the longer the cabbage is boiled, the less drops are needed. The graph shows the effect that cooking hat on food: because of the boiling, vitamins are lost. The loss of vitamins is due to the fact that when heated, the cell membranes burst, releasing the ascorbic acid. Vitamin C, the most reactive reducing agent known to occur naturally in living tissues, is an essential nutrient for humans. It is water soluble and is found in many foods, especially in plants. Lack of this vitamin in the diet, over a prolonged period of time will lead to the development of scurvy; low levels of this vitamin in the diet is also important for its antioxidant properties. This concludes that cabbage, as well as other vegetables is more beneficial for humans if consumed fresh.
The experiment has proved the aim and hypothesis: through boiling, vegetables loose vitamins. But even so, there were a few weaknesses in this experiment.
One of the main weaknesses might be that we did not count accurately the number of drops. We used a pipette to suck up water and add drop by drop to the DCPIP solution. But sometimes we might have squished to hard the pipette and drop a larger amount then we should have, therefore we had to approximate the number of drops that were added. To make this experiment more accurate we could have done a titration, and instead of measuring the drops needed to be added, we would have measured the millilitres.
Another weakness would be due to the leafs that were used to boil. For the experiment, we used a green cabbage which has leafs usually tightly compacted.