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: **
10, 28
18 cm
The rubber bands were measured using the doubly reduced ruler copies. I began measuring the rubber bands on the first end of each at the 10 cm mark on the ruler copy. The end mark for the first rubber band was 28 cm. I think my measurement is within + - .04 cm accurate. This rubber band is mark with a number 1.
** The basis for your uncertainty estimate: **
By using the doubly reduced ruler my measurements should be fairly accurate. However, they are copies and therefore there may be flaws in the copy or the fact that the ruler markings are so close together my human eyes may be playing tricks on me. Therefore, I estimated my uncertainty to be at least between .04 cm less and .04 cm great than the reported result because there is a little room for an uncertainty but not a huge amount because the ruler is fairly precise.
** Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino: **
10cm, 28cm
10cm, 28cm
10cm, 28.3cm
10cm, 28cm
10cm, 28cm
10cm, 28cm
END
18 cm +- .01cm, 18 cm +- .01cm, 18.3 cm +- .01 cm, 18 cm +- .01cm, 18 cm +- .01cm, 18 cm +- .01cm
1, 2, 3, 4, 5, 6
.04 cm uncertainty
** Distances between ends when supporting 2 dominoes **
10cm, 28.6cm
10cm, 28.6cm
10cm, 28.6cm
10cm, 28.6cm
10cm, 28.6cm
10cm, 28.6cm
** Lengths when supporting 4, 6, ... dominoes: **
10.0 cm, 28.8 cm; 10.0 cm, 29.0 cm; 10.0 cm, 29.3 cm; 10.0 cm, 28.8 cm; 10.0 cm, 29.3 cm; 10.0 cm, 28.8 cm
This result has 4 dominoes
10.0 cm, 29.6 cm; 10.0 cm, 29.6 cm; 10.0 cm, 29.6 cm; 10.0 cm, 29.6 cm; 10.0 cm, 29.6 cm; 10.0 cm, 29.6 cm
This result has 6 dominoes
10.0 cm, 29.9 cm; 10.0 cm, 29.9 cm; 10.0 cm, 30.0 cm; 10.0 cm, 30.0 cm; 10.0 cm, 30.0 cm; 10.0 cm, 29.9 cm
This result has 8 dominoes
END
** Your table of force in Newtons vs. length in cm for all rubber bands **
18 cm, 0.19 N
18.6 cm, 0.38 N
18.8 cm, 0.76 N
19.6 cm, 1.14 N
END
The first column of this table shows the length of the first rubber band from each set. The second column of the table shows the amount of force upon each domino in Newtons. The first line had one domino in the bag. The second line had 2 dominoes in the bag. Lastly, the third line had 4 dominoes and the fourth line had 6 dominoes in the bag.
** Describe the graph of your first rubber band **
My graph is increasing at a decreasing rate and then increasing at an increasing rate. My graph looks a little like the one shown above.
The shapes of all six rubber bands are a long oval shape. For this entire lab the thick rubber bands from the pack were used.
END
** The tension force in your first rubber band at length 9.8 cm: **
2.8 or 2.9 (from graph above)
** The length of your first rubber band when tension is 1.4 N: **
9.2 or 9.3 cm (from graph above)
** 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: **
.19 N, .50 N, .65 N, 1.1 N
0, 0.12, 0.11, 0.04 N
The first force was the same as the point because I started the curve at this point. The rest are off just slightly.
** 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: **
18.00 cm, 18.45 cm, 19.00 cm, 19.58 cm
18.00 cm, 18.60 cm, 18.80 cm, 19.60 cm
** The typical error you estimate when predicting force for a given length from your graphs: **
I have more faith in the values of the curve because this report suggested that the curve tends to show more accuracy than actual observation. The uncertainty in force is about +-0.7 N. To estimate I simply took the average of the differences among the 4 forces.
** The typical error you estimate when predicting length for a given force from your graphs: **
The estimated uncertainty is about +- .09 cm. Again to reach this conclusion I took the average of the four differences from the actual observation and the curve of the graph.
** **
3 hours
** **
In a few of the answers above I put (from the graph above) instead of using my graph didn't include down to 9.8 cm. The x-axis of my graph, the length, ranged from 17 cm to 20 cm.
Good information, and your descriptions of your graphs are good.