Doc Brown's Chemistry
SALTERS ADVANCED LEVEL CHEMISTRY
Scribbles on Error analysis in Activities EL 1.1 and EL 2.1
Return to My Salters AS homepage - "Unit EL Elements of Life"
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basically the % error is calculated as follows:
the 'error for that apparatus' x 100 / effective reading
there is guidance in the activities as to what the error is acknowledged to be
generally it is taken to be 1/2 of the smallest unit on the scale being used
eg if a balance weighs to 0.01g the error uncertainty is taken as 0.005g
In the case of EL1.1 there are three weighing errors to be added together.
BUT make sure you use the 'effective' results eg actual mass of copper etc.
NOT the original recorded weighings, eg if you did the experiment in a test tube + Xg Cu = 15g total, and somebody else did it in a pyrex boiling tube + Xg Cu = 30g total
the weighing error for 2dp balance is 0.005 x 100 / X
NOT 0.005 x 100 / 15 or 30, using a heavier pyrex tube will NOT halve the weighing error!
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