Rigel Posted April 2, 2011 Report Share Posted April 2, 2011 (edited) Hello IB Survival, i got some doubts about my experiment.It's about measuring the density of plasticine, i've got the raw values for the volume and the mass of the object, but, do i have to make a graph about the results? Or i just have to find the uncertainities of the values? And, if i have to make a graph, which program should i use? (With max and min gradients). The results were:Volume10ml11ml11ml11ml10ml11mlMass14.1g14.0g14.1g14.1g14.1g14.1gThose are the raw results. Once again, Do i have to make a graph about the results? Or it's not necessary? This is for the portfolio. Also, do i have to state the dependent/independent/controlled variables?Thank you guys very much! Edited April 2, 2011 by Ipos Manger Reply Link to post Share on other sites More sharing options...
Keel Posted April 3, 2011 Report Share Posted April 3, 2011 Hello,I take chemistry and not physics but I think I can help. If your task is to 'measure the density of plasticine' then you should proceed to do just that. In my opinion you wouldn't need a graph. Just find the density for each sample and average them and that would be your final answer. Then your proceed to find the random uncertainty in your answer. You then proceed on to do your Conclusion and Evaluation ().The chemistry forum has some reasources on how to do your IA, they should be similar. Reply Link to post Share on other sites More sharing options...
larry Posted April 3, 2011 Report Share Posted April 3, 2011 Basically, what Keel said. You don't have a big enough range of measurements to do a graph. Just find the density of each sample and then find the mean density.Is the portfolio something new? This seems like a very simple experiment, or is it part of a larger one? Reply Link to post Share on other sites More sharing options...
Keel Posted April 3, 2011 Report Share Posted April 3, 2011 Basically, what Keel said. You don't have a big enough range of measurements to do a graph. Just find the density of each sample and then find the mean density.Is the portfolio something new? This seems like a very simple experiment, or is it part of a larger one?They have plenty of values for a graph, the minimum requirement is five points, they have 6. The simple fact is that a graph would not show anything. What can you deduce from a line going across the page? Plus, the simpler the experiment the better the IA. Reply Link to post Share on other sites More sharing options...
larry Posted April 3, 2011 Report Share Posted April 3, 2011 Ipos manager does not have a set of values for which they could plot a graph with any meaning because their domain would be all of 10 - 11ml: they wouldn't have a line going across a page, they'd have a cluster of points. The requirement is for 5 DIFFERENT points, not 2 points at 10ml and 4 points at 11ml. If there was a greater range of volumes, e.g. 10-20ml, they could plot a graph of mass vs volume: "a line going across the page": and the gradient would be the density (mass/vol).And there are limits to simplicity: you're measuring something (density) that doesn't change, in which case all you're doing is measuring something, there's barely any calculation. Which is why I asked if it was part of a larger experiment, like seeing how density was affected by temperature. Reply Link to post Share on other sites More sharing options...
Rigel Posted April 3, 2011 Author Report Share Posted April 3, 2011 Hey guys, thank you all for your repplies! Actually, i managed to finish the report, and somehow i managed to make a graph, in which the gradient was very close to the actual density. I have some more doubts thou. In the volume, what would be the uncertainity? Would it be 0.5ml?Thanks. Reply Link to post Share on other sites More sharing options...
Keel Posted April 4, 2011 Report Share Posted April 4, 2011 It really depends on how you measured the volume. The apparatus should state the uncertainty. If not, a convention is that the uncertainty is half the smallest unit reading. e.g. a normal ruler would have a uncertainty of +/- 0.05 cm Reply Link to post Share on other sites More sharing options...
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