Measurements w/ Correct Sig Figs

AP Physics G12.P3

measurement

# and unit

accuracy

how close a measured value is to the true value of the quantity (being measured)

precision

1. degree of exactness with the measurement made/stated
   

2. how close a series of measurements are to one another

significant digits

# of digits known + estimated digits

systematic errors

errors every time you make a certain measurement

cause/effect of systematic errors

cause: calibration error, faulty procedures, poor assumptions

effect: higher/lower than true value = limit accuracy of measured value

fix systematic errors

1. compare my results to other results obtained independently

2. diff equipment/techniques

3. experimental procedure done on known values

4. adjusting procedures

random errors

errors that cannot be predicted

causes/effect of random errors

causes:

1. bad judgment in reading meter/scale

2. fluctuating experimental conditions

3. parallax error

effect: limits precision of experiment

fix random error

1. averaging multiple measurements (or ones taken by others)

2. standard deviation

3. standard deviation of average

parallax error

observer’s line of sight @ an angle w/ respect to measurement marking & true end of object being measured

error

difference between measured value and accepted value

relative error

error / accepted value

% error

what % of the accepted value the error represents

(value_measured - value_accepted)/ valued_accepted * 100%