C-115 is a spring made by Century Corp. It stretches very easily under a mass and can stretch fairly far while retaining its shape.
The following is the correlation between the spring C-115 and how far it stretches given a specific weight/force applied. The distance coefficient corresponds to the mass in that given Newton's Second Law, F = ma, the spring will stretch the given distance (in centimeters) when experiencing an acceleration of one m/s^2 (approximately 1/10 of a g). Looking at the chart then, this means that a mass of 209 grams will stretch the spring approximately one centimeter under an acceleration of 1 m/s^2. With respects to gravity, the spring will stretch 9.81 cm under a mass of 209 grams.
This chart can be used in the calibration of an accelerometer as described on How to Build an Accelerometer.
Slope: (m) -0.96830037
Intercept: (b) 5.173931181
distco = e^(m * ln(Mass) + b)
r^2: 0.999936756
r: -0.99996838
Mass (g)Dist Coeff Mass (g)Dist Coeff Mass (g)Dist Coeff
0 0 100 2.043664887 200 1.044533416
0.5 345.538966 100.5 2.033818932 200.5 1.042011068
1 176.6077202 101 2.024068923 201 1.03950107
1.5 119.2615689 101.5 2.014413459 201.5 1.037003332
2 90.26561373 102 2.004851163 202 1.034517763
2.5 72.72510781 102.5 1.995380687 202.5 1.032044275
3 60.95553861 103 1.986000706 203 1.029582778
3.5 52.50354126 103.5 1.976709923 203.5 1.027133186
4 46.13547479 104 1.967507066 204 1.024695413
4.5 41.1627145 104.5 1.958390885 204.5 1.022269371
5 37.17038237 105 1.949360155 205 1.019854976
5.5 33.89350572 105.5 1.940413675 205.5 1.017452145
6 31.15486173 106 1.931550263 206 1.015060793
6.5 28.83139663 106.5 1.922768763 206.5 1.012680839
7 26.8349785 107 1.914068038 207 1.0103122
7.5 25.10081729 107.5 1.905446973 207.5 1.007954796
8 23.58020896 108 1.896904474 208 1.005608547
8.5 22.23582964 108.5 1.888439465 208.5 1.003273372
9 21.03859154 109 1.880050891 209 1.000949194
9.5 19.9654874 109.5 1.871737716 209.5 0.998635934
10 18.99807876 110 1.863498923 210 0.996333516
10.5 18.12141413 110.5 1.855333513 210.5 0.994041863
11 17.32324098 111 1.847240505 211 0.991760898
11.5 16.59342226 111.5 1.839218934 211.5 0.989490548
12 15.9234982 112 1.831267854 212 0.987230738
12.5 15.30635276 112.5 1.823386335 212.5 0.984981394
13 14.73595666 113 1.815573463 213 0.982742443
13.5 14.20716733 113.5 1.807828341 213.5 0.980513814
14 13.71557145 114 1.800150086 214 0.978295433
14.5 13.25735992 114.5 1.792537832 214.5 0.976087232
15 12.82922783 115 1.784990727 215 0.973889139
15.5 12.42829349 115.5 1.777507934 215.5 0.971701084
16 12.05203279 116 1.770088629 216 0.969522999
16.5 11.69822528 116.5 1.762732004 216.5 0.967354815
17 11.3649098 117 1.755437264 217 0.965196465
17.5 11.05034764 117.5 1.748203627 217.5 0.963047882
18 10.75299186 118 1.741030324 218 0.960908998
18.5 10.47146147 118.5 1.7339166 218.5 0.958779749
19 10.20451978 119 1.726861712 219 0.956660068
19.5 9.951055981 119.5 1.719864929 219.5 0.954549892
20 9.710069509 120 1.712925531 220 0.952449156
20.5 9.480656681 120.5 1.706042813 220.5 0.950357796
21 9.261999229 121 1.699216079 221 0.94827575
21.5 9.053354429 121.5 1.692444646 221.5 0.946202954
22 8.854046566 122 1.685727839 222 0.944139348
22.5 8.663459536 122.5 1.679064998 222.5 0.94208487
23 8.481030401 123 1.672455472 223 0.94003946
23.5 8.30624377 123.5 1.665898619 223.5 0.938003056
24 8.138626875 124 1.659393809 224 0.935975599
24.5 7.97774525 124.5 1.652940422 224.5 0.933957031
25 7.82319892 125 1.646537846 225 0.931947292
25.5 7.674619041 125.5 1.640185482 225.5 0.929946325
26 7.531664928 126 1.633882737 226 0.927954071
26.5 7.394021411 126.5 1.62762903 226.5 0.925970474
27 7.261396486 127 1.621423788 227 0.923995477
27.5 7.133519226 127.5 1.615266445 227.5 0.922029025
28 7.010137908 128 1.609156447 228 0.92007106
28.5 6.891018337 128.5 1.603093247 228.5 0.918121529
29 6.775942347 129 1.597076306 229 0.916180377
29.5 6.66470645 129.5 1.591105095 229.5 0.914247548
30 6.557120618 130 1.585179091 230 0.912322991
30.5 6.453007191 130.5 1.579297779 230.5 0.910406651
31 6.352199882 131 1.573460655 231 0.908498476
31.5 6.254542879 131.5 1.567667218 231.5 0.906598412
32 6.159890038 132 1.561916978 232 0.90470641
32.5 6.068104134 132.5 1.55620945 232.5 0.902822416
33 5.979056199 133 1.550544159 233 0.90094638
33.5 5.892624903 133.5 1.544920634 233.5 0.899078252
34 5.808696 134 1.539338413 234 0.89721798
34.5 5.727161814 134.5 1.53379704 234.5 0.895365516
35 5.647920775 135 1.528296066 235 0.893520811
35.5 5.570876993 135.5 1.522835048 235.5 0.891683814
36 5.495939863 136 1.517413551 236 0.889854479
36.5 5.423023705 136.5 1.512031145 236.5 0.888032756
37 5.352047437 137 1.506687405 237 0.886218598
37.5 5.282934266 137.5 1.501381916 237.5 0.884411957
38 5.215611411 138 1.496114265 238 0.882612788
38.5 5.150009843 138.5 1.490884047 238.5 0.880821043
39 5.086064043 139 1.485690862 239 0.879036676
39.5 5.023711787 139.5 1.480534316 239.5 0.877259642
40 4.962893936 140 1.475414021 240 0.875489895
40.5 4.90355425 140.5 1.470329593 240.5 0.87372739
41 4.845639211 141 1.465280656 241 0.871972083
41.5 4.789097859 141.5 1.460266837 241.5 0.870223929
42 4.733881644 142 1.455287769 242 0.868482885
42.5 4.679944281 142.5 1.45034309 242.5 0.866748906
43 4.627241623 143 1.445432442 243 0.865021951
43.5 4.575731536 143.5 1.440555475 243.5 0.863301975
44 4.525373786 144 1.43571184 244 0.861588938
44.5 4.476129934 144.5 1.430901196 244.5 0.859882795
45 4.427963235 145 1.426123205 245 0.858183506
45.5 4.380838549 145.5 1.421377534 245.5 0.85649103
46 4.33472225 146 1.416663853 246 0.854805325
46.5 4.289582147 146.5 1.41198184 246.5 0.85312635
47 4.245387409 147 1.407331174 247 0.851454065
47.5 4.202108494 147.5 1.40271154 247.5 0.84978843
48 4.159717078 148 1.398122626 248 0.848129405
48.5 4.118186 148.5 1.393564126 248.5 0.84647695
49 4.077489197 149 1.389035737 249 0.844831027
49.5 4.037601651 149.5 1.38453716 249.5 0.843191596
50 3.998494346 150 1.380068099 250 0.84155862
50.5 3.960159171 150.5 1.375628264 250.5 0.839932059
51 3.922558975 151 1.371217367 251 0.838311876
51.5 3.885677419 151.5 1.366835125 251.5 0.836698033
52 3.849493988 152 1.362481258 252 0.835090493
52.5 3.813988945 152.5 1.35815549 252.5 0.833489218
53 3.779143289 153 1.353857548 253 0.831894173
53.5 3.744938726 153.5 1.349587164 253.5 0.83030532
54 3.711357633 154 1.345344071 254 0.828722624
54.5 3.678383029 154.5 1.341128008 254.5 0.827146048
55 3.645998546 155 1.336938715 255 0.825575557
55.5 3.614188401 155.5 1.332775938 255.5 0.824011116
56 3.582937371 156 1.328639423 256 0.822452688
56.5 3.552230766 156.5 1.324528922 256.5 0.820900241
57 3.522054408 157 1.320444189 257 0.819353739
57.5 3.492394611 157.5 1.316384981 257.5 0.817813147
58 3.463238152 158 1.312351058 258 0.816278432
58.5 3.434572262 158.5 1.308342184 258.5 0.814749561
59 3.406384598 159 1.304358124 259 0.813226499
59.5 3.37866323 159.5 1.300398649 259.5 0.811709213
60 3.351396622 160 1.296463528 260 0.810197671
60.5 3.324573617 160.5 1.292552539 260.5 0.808691839
61 3.29818342 161 1.288665457 261 0.807191685
61.5 3.272215585 161.5 1.284802064 261.5 0.805697178
62 3.24666 162 1.280962142 262 0.804208284
62.5 3.221506875 162.5 1.277145476 262.5 0.802724973
63 3.196746728 163 1.273351856 263 0.801247213
63.5 3.172370372 163.5 1.269581072 263.5 0.799774972
64 3.148368906 164 1.265832917 264 0.798308219
64.5 3.124733703 164.5 1.262107187 264.5 0.796846924
65 3.101456399 165 1.258403681 265 0.795391056
65.5 3.078528883 165.5 1.254722198 265.5 0.793940585
66 3.055943289 166 1.251062543 266 0.792495481
66.5 3.033691985 166.5 1.24742452 266.5 0.791055713
67 3.011767565 167 1.243807938 267 0.789621252
67.5 2.99016284 167.5 1.240212606 267.5 0.788192069
68 2.968870833 168 1.236638336 268 0.786768135
68.5 2.947884767 168.5 1.233084944 268.5 0.785349419
69 2.927198061 169 1.229552245 269 0.783935895
69.5 2.90680432 169.5 1.226040058 269.5 0.782527532
70 2.886697334 170 1.222548206 270 0.781124303
70.5 2.866871065 170.5 1.219076509 270.5 0.779726179
71 2.847319643 171 1.215624794 271 0.778333133
71.5 2.828037364 171.5 1.212192887 271.5 0.776945137
72 2.809018678 172 1.208780619 272 0.775562163
72.5 2.79025819 172.5 1.205387818 272.5 0.774184184
73 2.771750649 173 1.20201432 273 0.772811172
73.5 2.753490947 173.5 1.198659957 273.5 0.771443101
74 2.735474112 174 1.195324568 274 0.770079944
74.5 2.717695307 174.5 1.192007991 274.5 0.768721675
75 2.70014982 175 1.188710067 275 0.767368266
75.5 2.682833064 175.5 1.185430636 275.5 0.766019693
76 2.665740572 176 1.182169545 276 0.764675928
76.5 2.648867993 176.5 1.178926638 276.5 0.763336946
77 2.632211087 177 1.175701763 277 0.762002722
77.5 2.615765725 177.5 1.172494768 277.5 0.760673229
78 2.599527879 178 1.169305506 278 0.759348444
78.5 2.583493628 178.5 1.166133829 278.5 0.758028339
79 2.567659144 179 1.16297959 279 0.756712892
79.5 2.552020699 179.5 1.159842646 279.5 0.755402076
80 2.536574656 180 1.156722854 280 0.754095868
80.5 2.521317466 180.5 1.153620073 280.5 0.752794243
81 2.506245669 181 1.150534164 281 0.751497177
81.5 2.491355889 181.5 1.147464988 281.5 0.750204645
82 2.476644831 182 1.144412409 282 0.748916625
82.5 2.462109279 182.5 1.141376292 282.5 0.747633092
83 2.447746095 183 1.138356503 283 0.746354022
83.5 2.433552215 183.5 1.135352911 283.5 0.745079393
84 2.419524647 184 1.132365385 284 0.74380918
84.5 2.405660471 184.5 1.129393795 284.5 0.742543362
85 2.391956831 185 1.126438015 285 0.741281915
85.5 2.378410943 185.5 1.123497916 285.5 0.740024817
86 2.365020083 186 1.120573375 286 0.738772044
86.5 2.35178159 186.5 1.117664266 286.5 0.737523575
87 2.338692866 187 1.114770469 287 0.736279388
87.5 2.32575137 187.5 1.111891861 287.5 0.735039459
88 2.312954619 188 1.109028323 288 0.733803767
88.5 2.300300184 188.5 1.106179736 288.5 0.732572291
89 2.287785693 189 1.103345983 289 0.731345009
89.5 2.275408825 189.5 1.100526947 289.5 0.730121899
90 2.26316731 190 1.097722513 290 0.728902939
90.5 2.251058928 190.5 1.094932568 290.5 0.72768811
91 2.239081507 191 1.092157 291 0.726477389
91.5 2.227232924 191.5 1.089395696 291.5 0.725270756
92 2.215511099 192 1.086648546 292 0.724068189
92.5 2.203913999 192.5 1.083915442 292.5 0.722869669
93 2.192439632 193 1.081196275 293 0.721675175
93.5 2.181086052 193.5 1.078490938 293.5 0.720484686
94 2.16985135 194 1.075799326 294 0.719298182
94.5 2.158733659 194.5 1.073121334 294.5 0.718115644
95 2.147731151 195 1.070456858 295 0.716937051
95.5 2.136842036 195.5 1.067805796 295.5 0.715762383
96 2.126064561 196 1.065168045 296 0.71459162
96.5 2.115397008 196.5 1.062543506 296.5 0.713424744
97 2.104837696 197 1.059932079 297 0.712261735
97.5 2.094384976 197.5 1.057333665 297.5 0.711102573
98 2.084037235 198 1.054748167 298 0.709947239
98.5 2.07379289 198.5 1.052175488 298.5 0.708795714
99 2.063650392 199 1.049615533 299 0.70764798
99.5 2.053608221 199.5 1.047068207 299.5 0.706504017
The following shows the data used to calculate the regression line used above. Chips refer to poker chips used as incremental units during compilation.
Mass Grams Kg Dist-Coeff J/cm Ln(Mass) Ln(Dist Coeff)
00 Chips: 48.32 0.04832 4.137283226 0.19991 3.877845554 1.420039347
05 Chips: 107.72 0.10772 1.889491733 0.20354 4.679535268 0.636307869
10 Chips: 166.41 0.16641 1.257642275 0.20928 5.114454623 0.229238758
15 Chips: 224.61 0.22461 0.934823153 0.20997 5.414365565 -0.06739791
20 Chips: 284.06 0.28406 0.740954591 0.21048 5.649185483 -0.29981594