A clamp and stand should be used to hold the spring in place. Ensure its parallel to the stand using a ruler, this reduces the effect of random parralax error when measuring extension.Masses should be attached to the bottom of the spring. Increasing masses by equal increments (2, 4, 6, 8, 10.... kg).Before attaching any masses, measure the length of the unloaded spring with a ruler. Note this down.Once the spring is loaded, measure the length of the whole spring using a ruler, from the top of the spring to its bottom. Ensure its parallel to the spring when measuring.Repeat this experiment 3 times, recording the data in a table. (An example of the table can be drawn in your answer, 1 column for incrementally increasing masses, a column next to it of the masses multiplied by acceleration due to gravity for weight, 3 columns after that for (loaded length - unloaded length) for each attached mass, then a column after this for mean values of extension for each mass attached, then one more column for weight divided by mean extension)Mass values must be multipled by acceleration due to gravity, then divided by mean value of extension for each associated mass in question. This gets multiple values of spring constant, which you should then take the mean value.Sources of innacuracy - parallax errors due to not going exactly to the bottom of the spring, the ruler wasnt parralel to the spring. Also, the spring may have surpassed its limit of proportionality, meaning it no longer obeys Hookes Law, this should be able to be seen in results if some spring constants are way off.