Can you discuss the practical we completed in class today, I would like you to comment on the reliability, precision and accuracy of your results, and the method itself.
I worked with Kate and in our experiment, instead of using yeast, we used some other enzyme - the name of which escapes me - to make the beads. Our result was unreliable because:
--> Kate and I were recording the timings separately, so there must be some inconsistencies with our data. --> When we took measurements from the gas syringe, we decided to add 0.5's and 0.75's to our recording because the reading happened to be between two lines every time. Apparently, we weren't meant to do that. --> We started timing quite late. Our beads reacted at a significantly faster rate than the yeast beads and so by the time I started timing over half of the beads had already risen to the surface of the flask. Also, because the beads were reacting so fast, I suspect quite a lot of gas escaped out of the flask before I could put the bung in as well. --> At one point, when we were testing the bigger beads, the bung came out of the conical flask, so there would have been a lot of gas lost through that. Therefore our entire work was compromised :(
In terms of rectifying some mistakes, I would say some are really unavoidable, like the fact that the beads reacted way too fast for us and that the bung was too big to fit into the conical flask. Also, the gas syringes could do with a smaller scale (or is it bigger resolution?) so if there is a 0.5 or a 0.75 we can confidently write it down, not to mention the fact that it would be more precise as well.
Rachel and I worked together to carry out this experiment. I feel that the results that we collected for are experiment were unreliable. I feel that the results are unreliable because we encountered a number of problems that affected the consistency in our method and the overall accuracy of our results. - The first problem I feel that effected the reliability of are results was the syringe we used to produce are small beads This syringe did not have an exact reading of 10cm3, so we had to judge were we thought the measurement was. - Secondly we had trapped air in both are small and large bead syringes, this caused the production of beads to be slowed. In order to resolve the problem Rachel and I would remove the trapped air. However in this process we would often lose yeast mix or end up with larger sized beads. - Another problem we encountered was that from the minute some of the yeast beads were added to the hydrogen peroxide (?) they floated. However the majority of the beads took at least 15minutes before they began to float. - We tried to keep are water bath at a constant temperature, however it did fluctuate. This could have an effect on the enzymes in the yeast. - We also had the bung of the conical flask come lose/ out at some points in the experiment so O2 would have been lost. - I also felt that the resolution of the syringe collecting gas was not small enough to take accurate readings. I think that the method for this experiment was fine. However I feel that the equipment for this experiment could be improved, which would help to prevent some of the above mistakes occurring. I also think that if Rachel and I had taken more care when carrying out the experiment we could have resolved some of the issues relating to the unreliability of are results.
I was working with Sumiyyah and we also had some issues(mostly due to timing) that meant that none of my beads ended up rising to the surface(I don't remember if Sumiyyah's did or not). Though this may have also been due to the fact that the bung did not fit on my flask either, so as Csarina said any gas produced in that time would have escaped. I also agree with Csarina about the gas syringes, as it's quite difficult to accurately gauge the minute pressure changes. Apart from this, I believe we did everything else correctly, and the only real issue was time(or rather, lack of it)
I worked with Alysha on this practical. Unfortunately, we did not gain any results on the rate of reaction, this was due to the fact the experiment had not finished by the end of the lesson. I don't think our results would have been very accurate as we were working separately on the different sized beads due to the lack of time available, and we may have conducted the experiment differently. Furthermore, our investigation also involved random errors as we forgot to start the stop watch at the correct time which meant we did not have an exact time for the rate of reaction, affecting the reliability of our results. In order to check if our results were reliable, we could compare them to the other group who used the same procedure as we did. Nevertheless, we did try our best to be as accurate as we could, and we made sure that the same procedures were carried out on the different sized beads. What’s more, the small syringe did not show a clear reading for 10cm3, therefore we measured 10cm3 using the larger syringes and transferred the mixture to the small syringe, to ensure that the same volume was being used in both conditions of the experiment, making our results more accurate. However, because we used a larger syringe with a larger scale, our results may not have been very precise. Further to this, we made sure that the temperature of the water-bath remained constant throughout the investigation. This would have led to fewer extraneous variables affecting the reliability of our results leading to valid results and a fair test. Further assumptions could be made if we had some results!
• Air bubbles hindered our experiment as it prevented the solution from dripping out the syringes. This meant we had to squeeze the syringe to remove the air bubble and this resulted in us losing some of the mixture. Although this happened with both the smaller and large beads, it means we can’t be sure that we had the same volume of each mixture and therefore are results aren’t reliable. • As we measured the diameters of the beads with a school ruler this meant the highest resolution we had was mm. Due to the size of the beads being quite small, this meant our results lacked precision as we were having to round the measurements to the nearest millimetre rather than getting an accurate measurement. • As we had to make sure the water bath was staying at 40 degrees this left room to error. If we had placed them in a machine controlled water bath then that would have allowed us to be sure the water was always at 40 degrees rather than undergoing fluctuations which could have affected the enzymes. • The bung we placed in the test tubes to prevent the oxygen from escaping came loose several times so we can’t be certain we were able to measure all the oxygen. It was also hard to say for sure when the beads started to float as when we put them into the hydrogen peroxide some floated to the top immediately but then after that there were none others floating for at least 15 minutes.
I worked with Kate and in our experiment, instead of using yeast, we used some other enzyme - the name of which escapes me - to make the beads. Our result was unreliable because:
ReplyDelete--> Kate and I were recording the timings separately, so there must be some inconsistencies with our data.
--> When we took measurements from the gas syringe, we decided to add 0.5's and 0.75's to our recording because the reading happened to be between two lines every time. Apparently, we weren't meant to do that.
--> We started timing quite late. Our beads reacted at a significantly faster rate than the yeast beads and so by the time I started timing over half of the beads had already risen to the surface of the flask. Also, because the beads were reacting so fast, I suspect quite a lot of gas escaped out of the flask before I could put the bung in as well.
--> At one point, when we were testing the bigger beads, the bung came out of the conical flask, so there would have been a lot of gas lost through that. Therefore our entire work was compromised :(
In terms of rectifying some mistakes, I would say some are really unavoidable, like the fact that the beads reacted way too fast for us and that the bung was too big to fit into the conical flask. Also, the gas syringes could do with a smaller scale (or is it bigger resolution?) so if there is a 0.5 or a 0.75 we can confidently write it down, not to mention the fact that it would be more precise as well.
In regards to rectifying some mistakes, what about varying the concentration of sodium hydroxide?
DeleteRachel and I worked together to carry out this experiment. I feel that the results that we collected for are experiment were unreliable. I feel that the results are unreliable because we encountered a number of problems that affected the consistency in our method and the overall accuracy of our results.
ReplyDelete- The first problem I feel that effected the reliability of are results was the syringe we used to produce are small beads This syringe did not have an exact reading of 10cm3, so we had to judge were we thought the measurement was.
- Secondly we had trapped air in both are small and large bead syringes, this caused the production of beads to be slowed. In order to resolve the problem Rachel and I would remove the trapped air. However in this process we would often lose yeast mix or end up with larger sized beads.
- Another problem we encountered was that from the minute some of the yeast beads were added to the hydrogen peroxide (?) they floated. However the majority of the beads took at least 15minutes before they began to float.
- We tried to keep are water bath at a constant temperature, however it did fluctuate. This could have an effect on the enzymes in the yeast.
- We also had the bung of the conical flask come lose/ out at some points in the experiment so O2 would have been lost.
- I also felt that the resolution of the syringe collecting gas was not small enough to take accurate readings.
I think that the method for this experiment was fine. However I feel that the equipment for this experiment could be improved, which would help to prevent some of the above mistakes occurring. I also think that if Rachel and I had taken more care when carrying out the experiment we could have resolved some of the issues relating to the unreliability of are results.
I was working with Sumiyyah and we also had some issues(mostly due to timing) that meant that none of my beads ended up rising to the surface(I don't remember if Sumiyyah's did or not). Though this may have also been due to the fact that the bung did not fit on my flask either, so as Csarina said any gas produced in that time would have escaped. I also agree with Csarina about the gas syringes, as it's quite difficult to accurately gauge the minute pressure changes.
ReplyDeleteApart from this, I believe we did everything else correctly, and the only real issue was time(or rather, lack of it)
I worked with Alysha on this practical. Unfortunately, we did not gain any results on the rate of reaction, this was due to the fact the experiment had not finished by the end of the lesson. I don't think our results would have been very accurate as we were working separately on the different sized beads due to the lack of time available, and we may have conducted the experiment differently. Furthermore, our investigation also involved random errors as we forgot to start the stop watch at the correct time which meant we did not have an exact time for the rate of reaction, affecting the reliability of our results. In order to check if our results were reliable, we could compare them to the other group who used the same procedure as we did.
ReplyDeleteNevertheless, we did try our best to be as accurate as we could, and we made sure that the same procedures were carried out on the different sized beads. What’s more, the small syringe did not show a clear reading for 10cm3, therefore we measured 10cm3 using the larger syringes and transferred the mixture to the small syringe, to ensure that the same volume was being used in both conditions of the experiment, making our results more accurate. However, because we used a larger syringe with a larger scale, our results may not have been very precise. Further to this, we made sure that the temperature of the water-bath remained constant throughout the investigation. This would have led to fewer extraneous variables affecting the reliability of our results leading to valid results and a fair test.
Further assumptions could be made if we had some results!
• Air bubbles hindered our experiment as it prevented the solution from dripping out the syringes. This meant we had to squeeze the syringe to remove the air bubble and this resulted in us losing some of the mixture. Although this happened with both the smaller and large beads, it means we can’t be sure that we had the same volume of each mixture and therefore are results aren’t reliable.
ReplyDelete• As we measured the diameters of the beads with a school ruler this meant the highest resolution we had was mm. Due to the size of the beads being quite small, this meant our results lacked precision as we were having to round the measurements to the nearest millimetre rather than getting an accurate measurement.
• As we had to make sure the water bath was staying at 40 degrees this left room to error. If we had placed them in a machine controlled water bath then that would have allowed us to be sure the water was always at 40 degrees rather than undergoing fluctuations which could have affected the enzymes.
• The bung we placed in the test tubes to prevent the oxygen from escaping came loose several times so we can’t be certain we were able to measure all the oxygen. It was also hard to say for sure when the beads started to float as when we put them into the hydrogen peroxide some floated to the top immediately but then after that there were none others floating for at least 15 minutes.