rubber band calibration

Your work on rubber band calibration 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:

10.0, 21.5

Using the 1x reduced ruler I divided 11.5 by 1.6 (the scale between rulers) to get 7.19cm, rounded to two decimals. My uncertainty is 7.16-7.22cm.

The basis for your uncertainty estimate:

The 1x reduced ruler is scaled 1:1.6 on the control ruler. So every .1cm on the 1x reduced ruler .0625cm on the control ruler. Taking half of this accurate value and adding and subtracting to either side gives me my desired uncertainty to within .03cm.

Positions of the ends of each rubber band, actual lengths of each when the chain supports 1 domino:

10.0, 21.5

end

7.19, 7.19, 7.19, 7.19, 7.19

Uncertainty +-.03

Distances between ends when supporting 2 dominoes

7.31, 7.31, 7.31, 7.31, 7.31

From the weight of 2 dominos.

Lengths when supporting 4, 6, ... dominoes:

7.50, 7.50, 7.50, 7.50, 7.50

7.69, 7.69, 7.69, 7.69, 7.50

7.88, 7.88, 7.88, 7.81, 7.81

8.06, 8.06, 8.06, 8.00, 7.88

Note: maximum of 10 dominos failed to stretch any rubber bands beyond 30% of original length

Your table of force in Newtons vs. length in cm for all rubber bands

7.19, 7.19, 7.19, 7.19, 7.19, .19

7.31, 7.31, 7.31, 7.31, 7.31, .38

7.50, 7.50, 7.50, 7.50, 7.50, .76

7.69, 7.69, 7.69, 7.69, 7.50, 1.14

7.88, 7.88, 7.88, 7.81, 7.81, 1.52

8.06, 8.06, 8.06, 8.00, 7.88, 1.9

Describe the graph of your first rubber band

1st: Increasing at a constant rate

2nd: Increasing at a constant rate

3rd: Increasing at a constant rate

4th: Increasing at a constant rate then increasing at an increasing rate then increasing at a decreasing rate

5th Increasing at a constant rate then increasing at an increasing rate then increasing at a decreasing rate then increasing at an increasing rate

The tension force in your first rubber band at length 9.8 cm:

5.3

The length of your first rubber band when tension is 1.4 N:

7.8

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:

.16, .40, .78, 1.14, 1.52, 1.88

.03, .02, .02, .01, 0, .02

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:

7.20, 7.30, 7.49, 7.69, 7.88, 8.07

.01, .01, .01, 0, 0, .01

The typical error you estimate when predicting force for a given length from your graphs:

I have more faith in the curve because it appears to evenly pass between all points. I estimate my uncertainty is +-.03 because that is the largest error recorded.

The typical error you estimate when predicting length for a given force from your graphs:

I estimate my uncertainty is +-.01 because that is the largest error recorded.