Your 'rubber band calibration' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** Your initial comment (if any): **
** first line ruler markings, distance in actual cm between ends, how obtained: **
0,7.30
7.30
This is the length of the first rubber band using a weight of one domino. The rubber band is marked with one red stripe. Measurement is good to within +/- .1 Centimeter. I can't read any closer than that. Too much movement.
** The basis for your uncertainty estimate: **
Just my best judgement based on my ability to measure a piece that moves with 50 year old eyes! I found it much easier to move the ruler and start from zero on each measurement.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
0,7.30
0,7.20
0,7.10
0,7.00
0,7.10
0,7.20
END
7.30,7.20,7.10,7.00,7.10,7.20
1,2,3,4,5,6
+/-.1 cm
** Distances between ends when supporting 2 dominoes **
7.40,7.40,7.20,7.20,7.30,7.40
These are the lengths with a weight of two dominoes
** Lengths when supporting 4, 6, ... dominoes: **
7.6,7.6,7.5,7.4,7.5,7.5
4
7.8,7.8,7.6,7.5,7.6,7.7
6
8.0,8.0,7.8,7.7,7.8,7.9
8
8.2,8.2,8.0,7.9,8.0,8.1
10
8.4,8.3,8.2,8.1,8.2,8.3
12
8.5,8.5,8.4,8.3,8.4,8.5
14
8.7,8.7,8.6,8.5,8.6,8.7
16
9.0,9.0,8.8,8.6,8.7,8.8
18
9.1,9.0,9.0,8.8,9.0,8.9
20
END
** Your table of force in Newtons vs. length in cm for all rubber bands **
7.4,7.4,7.2,7.2,7.3,7.4,.38
7.6,7.6,7.5,7.4,7.5,7.5,.76
7.8,7.8,7.6,7.5,7.6,7.7,1.14
8.0,8.0,7.8,7.7,7.8,7.9,1.52
8.2,8.2,8.0,7.9,8.0,8.1,1.9
8.4,8.3,8.2,8.1,8.2,8.3,2.28
8.5,8.5,8.4,8.3,8.4,8.5,2.66
8.7,8.7,8.6,8.5,8.6,8.7,3.04
9.0,9.0,8.8,8.6,8.7,8.8,3.42
9.1,9.0,9.0,8.8,9.0,8.9,3.8
END
** Describe the graph of your first rubber band **
All my graphs for all 6 rubber bands were nearly linear with all increasing at a constant rate throughout the range of .38 to 3.8 newtons
** The tension force in your first rubber band at length 9.8 cm: **
5.3
7.9
** The length of your first rubber band when tension is 1.4 N: **
** The forces at your observed lengths the 1st rubber band, as given by the curve, and the deviations of those curve-predicted lengths from the observed lengths: **
My best fit line was straight and fit the points so well that it's hard to really discern any significant difference since most of the points fall on the best fit line.
** The lengths predicted for forces .19 N, .38 N, .76 N, 1.14 N, etc. by the curve for your first rubber band; the deviations of your actual observations from these predictions: **
7.3,7.5,7.6,7.8,8.0,8.2,8.3,8.5,8.8,9.0,9.2
0.0,0.1,0.0,0.0,0.0,0.0,0.1,0.0,0.1,0.0,0.1
** The typical error you estimate when predicting force for a given length from your graphs: **
I would have more faith in the best fit line because it tends to smooth and normalize the data. I think uncertainty on force is about +/- .1 newtons.
** The typical error you estimate when predicting length for a given force from your graphs: **
My uncertainty on the is about twice the number of force units since the scale is almost twice as large so uncertainty on length is about +/-.15 cm
** **
3.0 hours
** **
took alot of time.
You appear to have made careful observations, which should give you good results when you use these rubber bands in subsequent experiments.