ineedyouubiebs 2 years ago I know this is not math but whatever. If the mass is 1.16 and the volume is 8.5 what is the slope?

1. ineedyouubiebs

In my HW it says to find the slope it's (change in mass)/(change in volume)

2. ineedyouubiebs

3. Luigi0210

Do you know the changes?

4. ineedyouubiebs

What do you mean by that?

5. Luigi0210

Do you only have one set of values?

6. ineedyouubiebs

Oh no there's more. Want me to put them up?

7. ineedyouubiebs

Label 1) mass: 1.16 g volume:8.5 . Label 2) mass:0.98 volume: 7.2. Label 3) mass: 1.13 volume:10.0 . Label 4) mass: 0.69 volume: 6.2. Label 5) mass: 0.83 volume:6.0. Label 6) mass:1.45 volume: 12.9. Label 7) mass: 0.88 volume: 7.9. Label 8) mass: 1.03 volume: 7.5. Label 9) mass: 0.74 volume: 5.4. Label 10) mass: 1.02 volume: 7.5

8. ineedyouubiebs

Sorry I couldn't lined them up well I'm on my iPad right now

9. Luigi0210

Uhm

10. ineedyouubiebs

Yeah?

11. Luigi0210

I got nothing, sorry

12. kantalope

what happens if you treat the mass as the x coordinate and the volume as the y coordinate?

13. ineedyouubiebs

But that'll mean graphing all 10 of them

14. kantalope

ya working on ti

15. ineedyouubiebs

@dumbcow @dan815 got any ideas how to do this?

16. ineedyouubiebs

@Luigi0210 don't worry(:

17. ineedyouubiebs

@zepdrix ?

18. kantalope

tryin to find a website the will plot all the points

19. ineedyouubiebs

Okay thanks

20. zepdrix

kant, use this site, it's quite good :) https://www.desmos.com/calculator

21. kantalope

looks like the slopes are about the same for a series of points...not sure what the question is looking for

22. kantalope

thanks zepdrix i'll check that site too...the one i found called http://openstudy.com/study#

23. kantalope

I'm missing clone wars for this!

24. ineedyouubiebs

@kantalope lol my bad and how does this help me find what I'm looking for?

25. kantalope

typically when you are looking for slope you are looking for the change in whatever based on the change in the other thing.....these changes aren't a straight line. what else does the question have?

26. ⒶArchie☁✪

it is a bit confusing that a slope can be asked when mass and volume are given. However, if the slope is meant to mean density, then I will say the slope= mass/volume.

27. kantalope

if the data has a function we can find the variable slope based on the derivative of the function

28. kantalope

heh - I'll bet I'm supposed to be able to figure out this kind of problem at the end of the semester not the beginning...and the martini I just finished in not helping...

29. kantalope

I'm rearranging the data on the graph...

30. ineedyouubiebs

http://mcpchemistry1.wikispaces.com/file/view/HW4%20-%20Density%20Graph%20Practice%202013-14.doc/447730728/HW4%20-%20Density%20Graph%20Practice%202013-14.doc here is my HW, the question is on the last page

31. kantalope

The points are all squirrely so a serious person would do some stat regression to find the mean

32. kantalope

Ah ha...which is exactly what the graph was finding

33. ineedyouubiebs

I think your looking at the wrong page, it's the very last one

34. kantalope

right so my pictures were plots of the data that we were given...it is all wonky

35. kantalope

If we were measuring stuff that had a consistent mass to volume ratio the line would be nice and straight....the more stuff we had the more it would weigh yea?

36. ineedyouubiebs

Yeah it is all "wonky" ughhh this is irritating

37. kantalope

that's ok that is how real data works

38. ineedyouubiebs

Yeah, I know what your saying

39. ineedyouubiebs

You sure I'm not just suppose to divide or subtract?

40. kantalope

so our data is sloppy could mean a couple of things like the hint suggests - maybe some of the chunks we are looking at are real rocks and some are plastic fake rocks

41. ineedyouubiebs

Their metals

42. kantalope

nah if you were serious about this data you would plot it out like we did and look if it was in straight lines...if it was not you would do a process called regression to find the average slope between the plot points

43. kantalope

right so some of metal is real and some of it isn't or some of the metal is a different kind or you could just be kinda sloppy in measuring the volume or the mass...rounding up sometimes and rounding down others or if you have different people doing the measuring the data will get screwy

44. ineedyouubiebs

Becauseatfirst I taught I was only suppose to divide and ill get the answer, but apparerently not

45. kantalope

So for the last page you can paste in the plots in the pictures and a hypothesis is that the measurements are not consistent and that there seems to be two different trend lines in the data so there are probably two different kinds of metal in the sample with two densities regression wiki: http://en.wikipedia.org/wiki/Least_squares

46. kantalope

If you did just divide each set of points to get a series of numbers....I'll bet you get two sets of answers...lemme check that

47. ineedyouubiebs

Okay(:

48. kantalope

actually turns out that there are more like 3 sets of ratios - .14 is the answer to 3 samples .111 to three and .138 to three more <-- this also points to something funny with the data if the ration of volume to mass was the same all the samples would have basically the same well ratio ya ----so just dividing would show something but the graph makes it easier to see

49. mary.rojas

Can you explain in a different way, she cant understand

50. kantalope

If the samples were consistent - all made of the same stuff - if you had more stuff it would weigh more....a big gold coin has more mass (weighs more) than a small gold coin...and that change in size and mass would be consistent. A coin that is twice as big would weigh twice as much....does that make sense?

51. ineedyouubiebs

Yes, I do understand that thAt was one of the questions lol

52. kantalope

so if i started handing you coins that were twice as big but didn't weigh twice as much ...you would say "dood, you are rippin me off, these are not gold coins" that is what the first graph is showing ....there are four coins in the top line with a certain volume to weight ratio (slope) and then 6 coins in another line with a different volume to weight ratio(slope)

53. ineedyouubiebs

Somehow I think I'm just suppose to divide, and I'm just complicating myself!

54. kantalope

well number 2 on the second to last page says graph it....so there is that

55. ineedyouubiebs

Yeah and I already graphed it

56. kantalope

and the graph show some dots that make a line and some other dots that make a different line?

57. ineedyouubiebs

Yeah they do

58. kantalope

so the last question says to calculate the slope of each of those lines m= (y1-y0) / (x1-x0) if you pick any two points on the two lines you can get the slope

59. ineedyouubiebs

Can you do the first one as an example? Please

60. kantalope

ok top line the first point is (.69, 6.2) and another point on that line looks like (1.45, 12.9) would you agree?

61. kantalope

y1= 12.9 y0 = 6.2 x1= 1.45 x0 = .69 6.7/.76 = 8.82

62. ineedyouubiebs

No it's suppose to be 1.16 and 8.5

63. kantalope

the points on the other line are (0.74,5.4), ( 0.83,6.0), ( 0.98, 7.2), ( 1.02 ,7.5), ( 1.03, 7.5), (1.16,8.5) you can use any of those points to calculate the slope of the second line

64. kantalope

I started with the top line....that point is on the lower line...you can go with whatever one first

65. ineedyouubiebs

So I'll divide it like 1.16/8.5 correct?

66. kantalope

not if you want to calculate the slope like the last question asks...dividing will just get you the ratio not the slope...

67. kantalope

I made the graph bigger so it is easier to see the two different lines....we are looking for the slope of those two lines I think that the instructions are confusing as they ask for the change in mass over the change in volume....simply dividing is not the change....it is just the mass over the volume...in order to get the change part you have to do the y1-y0 thing

68. kantalope

I hope that means you are going ...ah, I get it rather than ah @\$%\$ it =)

69. ineedyouubiebs

Ahhhh crap? Lol I think I'm complicating it more that I should that's why , but that's all

70. kantalope

k gl im out its really late here

71. ineedyouubiebs

Yeah get some sleep goodnight

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