The forum discussion revolves around calculating the mass of marbles using data from a physics homework assignment based on the Millikan experiment. The user provided a list of container masses and calculated averages, ultimately concluding that the mass of one marble is approximately 20.33 g, which contradicts the known weights of the containers. Participants emphasized the importance of grouping containers by similar masses and taking into account the experimental uncertainty, suggesting that the mass of one marble is likely around 4.5 g, not the initial estimate. The discussion highlights the necessity of logical reasoning and data organization in solving such problems.
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Masses of all 10 containers in ascending order:hutchphd said:Please show all the data (where are the 31.5g samples?). Get organized please. Then suppose the marbles are ~4g. Does this work? What is the weight of the empty?
As I already said,orangegalaxies said:Step 2: I already found the differences in mass, could you explain more on what I need to do?
As implied by what I said, what you need to do is first figure out what the difference in masses is equal to and, once you answer that, guess the mass of one marble. The number should be consistent with you already know or is given.kuruman said:Why take differences and how do they help you guess the mass of one marble?
Why did you do this? Container+marbles masses at 32g. There are at most 6 marbles by question. What is minimum possible mass of container?orangegalaxies said:hmmm okay so for the 31-32 g container, i did 31-3 and then divided this by 4, but this is wrong like you said. I'm not sure as to what else i can do :')
The difference in masses:kuruman said:As I already said,
As implied by what I said, what you need to do is first figure out what the difference in masses is equal to and, once you answer that, guess the mass of one marble. The number should be consistent with you already know or is given.
3 g. Pls chill, I'm new to these concepts, not an expert so I won't be able to understand things unless you explain them. My teacher is crappy and won't explain either.hutchphd said:Why did you do this? Container+marbles masses at 32g. There are at most 6 marbles by question. What is minimum possible mass of container?
hmmmm. these are the values my teacher gave me...Charles Link said:I think that 3 gram minimum is inaccurate, and is resulting in extra confusion. I estimate the container to be closer to 2 grams.
Can't be 7 marbles by definition. Mass of marble is more like 4.5, Try another guess. It won't be perfect.orangegalaxies said:Largest mass: 31.9 g
Approx weight of one marble: 4 g
Mass of empty container: minimum of 3 g
(31.9 - 3)/4 = 7 marbles in largest container
This is wrong, I don't follow what you are saying, can you please explain?
Can you explain how you got 4.5 g?hutchphd said:Apologies. You almost got it but you need to choose best values from noisy data:
Can't be 7 marbles by definition. Mass of marble is more like 4.5, Try another guess. It won't be perfect.
Now make guess and plot mass vs # marbles for all data points.
Yeah you're right that is a pattermCharles Link said:If you look at the data, at first glance, (I'm sure you observed it as well), there appears to be increments of between 4.5 and 5 grams. There is a jump from 11 to 21, but with a small sample, it's not surprising that the 16 is absent.
I disagree I think it is more like 6g. The problem says >3.Charles Link said:I think that 3 gram minimum is inaccurate, and is resulting in extra confusion. I estimate the container to be closer to 2 grams.
see my post 42 :)hutchphd said:I disagree I think it is more like 6g. The problem says >3.
This is also true yeahCharles Link said:I just spotted something else=they give you the weight of the container to be at least 3 grams=it might even be large enough to make the 11 g have just one marble=my previous post on this being inaccurate and possibly 2 grams was incorrect.
graph the differences in masses?hutchphd said:Yes Now the OP needs to graph the data, draw the best linear fit. Slope gives marble mass, intercept gives container mass
in your previous post, is there any way you found the marble mass = 4.5 g? calculations i meanhutchphd said:Your eyeball and ruler will draw the "best" line pretty well. Gives the best fit to all the data.
sure, but as Charles mentioned, y=total measured mass vs. x=number of marbles. To find the number of marbles I need the mass of one so I wanted to know how you can say its 4.5 ghutchphd said:Rough graph in my head. Do the graph. Excel?
The increments are about 4.5 other than the missing 16. This is a very simple graph to draw by hand=if you have some graph paper it helps. Otherwise EXCEL is often used, but that can take some work to learn.orangegalaxies said:in your previous post, is there any way you found the marble mass = 4.5 g? calculations i mean
Hello, after graphing, I got a slope of 4.49992 and a y-intercept of 3.00000061. Is this reasonable?hutchphd said:You only need the integer number of marbles to plot the data. I guessed the 4.5 because it seemed to give integers within reasonable error limits. The error in the mass obtained from the best fit line (slope) from the graph should be good to a few percent. This slope in the Millikan oil drop experiment gave Millikan the charge increment for little balls of oil, electron by electron as he irradiated them). A truly beautiful experiment.
Incidentally it is possible that all the changes in the graph involved always moving 2 marbles (or3 or4) but it is less and less likely More data would make it more certain.
Please draw the graph. I don't think you graphed it, because I just graphed it, and I got round numbers, but not real close to 4.5, and certainly not 3 for the other number. The accuracy is only one decimal place or thereabouts.orangegalaxies said:Hello, after graphing, I got a slope of 4.49992 and a y-intercept of 3.00000061. Is this reasonable?
The graph shows this answer very clearly, and I'm hoping the OP will draw the graph like I did to see this for himself.hutchphd said:And I think the first data cluster is for n=1 marble so the mass of the container is ~6g