Surface area to volume ratio Time taken for HCL acid to diffuse (seconds)
14 38
9 90
7.3 139
6.5 178
6 185
3. Do your results support your hypothesis, use date from your table and graph to support your answer, you should also identify any anomalous results.
My hypothesis was ‘as the surface-area-to-volume ratio decreases the diffusion rate increases’ my results support my hypothesis, because in my table of results when the surface area to volume ratio is at 14 the diffusion time is 38 seconds, then the ratio goes down to 9, and the time increases to 90 seconds. My graph also supports my hypothesis, because the curve on my graph slopes down which shows as the diffusion time increases the ratio decreases. One of my results that could possibly have been an anomalous result was the last one because the difference in time between the last 2 is much less than the different between the others.
4. What are the limitations of this experiment, why might the results be inaccurate?
One thing which could affect the accuracy of the results was the fact it was difficult to judge when the cubes were clear, one person’s perspective of the cube being clear would probably be different to someone else’s, and the human eye isn’t really good enough to judge a measurement such as this, so it was difficult to judge what was ‘clear’. It was also difficult to cut the cubes 100% accurately, so the measurements were probably not as reliable as they could have been. Another thing which was difficult to make 100% accurate was the amount of HCL used because even know we were using syringes, it was difficult to get exactly 2cm3 each time.
5. What could you do to make these results more reliable? We could have used more professional equipment to do this experiment to ensure maximum reliability; also we should have had the same person judging the clarity every time. If we had something which helped us to measure the cube sizes to the exact millimetre rather