11th Grade HL Biology – Ms. Bartels
Due Monday October 21st
Limitations on Cell Size
Research Question: What is the correlation between surface-to-volume ration and ion exchange and how does this relate to cells? Evaluation of Method and Results:
Errors/ Limitations:| Suggestions for improvement:| Impact on Results:| Precision - Human error –cutting cubes freely, resulting in very different sized cubes, especially for the 1cm x 1cm x 1 cm cubes. All the cubes also had slightly diagonal edges. | One could use laser machines, as university level experimenters do, knife machines (which work by having knives attached to a machine which moves these knives the exact amount electronically imputed on it) or simply cookie cutters or anything that has a fixed shape to it. These are all realistic suggestions, although the price range varies.| As the aim of the experiment was not to predict the exact rate of ion exchange for an exact surface area-to-volume ratio, and rather prove a association or correlation between the two, this wasn’t extremely significant to the results. We still obtained a graph, which clearly shows this relationship.| Precision - Human Error – the stirring of the cubes was assigned to different people for different trials, thus changing the rate at which they were stirred at, and affecting the overall result of the single experiments. Sometimes, the rod would also touch the cubes, influencing its results.| A machine, which would stir at a single speed, also known as a dynamo-eletric machine. A cooking mixer would also work for this experiment if set at its lowest speed. Or we could just simply have one person stir the entire time, keeping it hand motions as constricted as possible, to minimize the risks as much as possible.| This did not have a large influence on our results, as they all showed an acceptable relationship in the end, however different it would have been if we had stirred correctly.| Reliability – The...