The filament bulb obeys ohms law Essay Example for Free

The filament bulb obeys ohms law EssayI think this was caused by air already in the subway creation pushed out. To overcome this I could have measured how much O2 started in the tube and thusly subtracted that from my beginning(a) measurement. My experiment was good because it was repeated enough times, three times, so that any(prenominal) unnatural results could be clearly seen next to a best- go yield. Also all of my results had a best-fit curve and the values increase throughout, backing up my prediction that as the subst set out concentration increased so would the initial rate of reaction. Using a measuring piston chamber rather than a gas syringe to collect the O2 is better(p) because gas syringes, although easier to use, do not always move with ease when oxygen moves in. In my experiment the oxygen bubbles could be clearly seen in the water inside the measuring cylinder and had no trouble make the cylinder. Limitation How does this affect accuracy and/or depe ndableness? Importance? Why? Modifications O2 escaping due to tubes in bung. If O2 flee then the volume of O2 accumulate will be wrong and in that locationfore the result could not be reliable.This is very roughly-valuable as if gas was escaping then it would not have got into the tube, at that placefore affecting the add up of O2 collect in the experiment. However, as the selfsame(prenominal) equipment was used throughout this is not a very important factor as it would have been the same for all of the experiments. Use Vaseline around tubes to stop O2 escaping and look for any gas escaping through holes in the tube that is in the water. This would stop O2 escaping but wouldnt really alter the reliability too much, just the accuracy of the result. Surface ara of barm not being similar.This is a shifting and therefore not keeping it the same means two things are being investigated at the same time, and therefore this would mean that the results gathered do have some inacc uracies and can not be reliable. This is the most important factor because a larger surface area means that there will be more to react with. If there were a very small surface area the reaction would be slow, as there is not much for the substrate to react with. By crushing the yeast up with a pestle and mortar the surface areas will all be the same but this would bucket along up the reactions dramatically as it would give the maximum surface area.This would have made the results a mint candy more reliable as they all would have begun with the same surface area. Test tube containing O2 in the lead H2O2 was added. This means that the first measurement could be quite high, when there is little activity, as solution being pushed in it pushes oxygen out through the tube. This is important as it explains the 1st result being much faster than the 2nd throughout the 5 experiments. However, it is the same for all of the experiments so it wouldnt make a bighearted difference in the comp arison of my results. Making a vacuum around the experiment would stop O2 getting into the tube.An easier alternative would be to measure O2 in tube before and then subtract that number from my 1st measurement. Although this would increase accuracy it would not alter the reliability, as the amount of O2 in the tube is the same severally time. Obstruction in the tube This would slow or stop the movement of O2 through to the measuring cylinder. If there was a block then it would cause the results to be much lower than they should be, with a much slow-moving initial rate of reaction. This is because less O2 is being measured as less would get to the measuring cylinder.By rinsing out the tube before each experiment any obstructions can be removed. If there were an obstruction then doing this would make the results more reliable and much more accurate. The results that I gathered, in my opinion, are not all reliable. This is mainly due to the wide range of results gathered in my 5ml H 2O2, the final measurements being 45cm3, 93cm3 and 92cm3. Also, my 2ml H2O2 experiment ended up with a higher initial rate of reaction and more O2 collected than the 3ml H2O2 and the 4ml H2O2 experiments. Repeating the experiment 3 times and then taking an average helps to hide these unreliable results.another(prenominal) reason why my results are unreliable is that the surface area was not the same each time. If the yeast in one experiment had a much higher surface area then it was departure to have a much faster initial rate of reaction than an experiment where yeast had a small surface area. This is likely to be why my 2ml H2O2 experiment came out higher than my 3ml and 4ml H2O2 experiments On my graphs I have circled what I think are anomalous results. My first anomalies occur on my 2ml H2O2 graph. Between 40seconds and 60seconds the O2 collected is 14. 3cm3, 17. 7cm3 and 21. 7cm3.I think that, although the graph on the whole is unreliable, these are anomalous because they do not fit the best-fit curve. On the 3ml H2O2 graphs I have circled two points as these points dip below the best fit curve and then back up again. At 70seconds and 80seconds the O2 collected is 20. 7cm3 and 22. 7cm3. A possible reason for this could have been that the tube might have been blocked, maybe by the way that the measuring cylinder was held. It might have been distinguishable if the measuring cylinder was clamped so it couldnt move and therefore couldnt squash the tube.By holding the measuring cylinder it was possible that it may have been pressed down on the tube briefly. This would of held the O2 in the tube and then when it was released the O2 would have all come out at once, resulting in the points moving back to the best-fit line. On the 5ml H2O2 graph I have circled one point. This point is after 30seconds and misses the best-fit curve by about 4cm3 it has 30cm3 whereas the curve crosses 30seconds at 34cm3. The reason for this anomaly could have been the same as abov e or possible because of a variation inaccuracy.Also, when holding the measuring cylinder, it was not always held perfectly upright, and therefore could have given a fancied reading but this is likely to have been the same throughout the experiment.Bibliography These are the books from which I gathered my learning and used to make my prediction Indge, Rowland, Baker, (2000) A New Introduction to Biology (Hodder Stroughton) Jones, Forsbery and Taylor (2000) Biology 1 (Cambridge University Press) Toole, Glenn and Susan (1999) intelligence Biology, Fourth Edition (Stanley Thorne Ltd).