1. Uncertainties and Error

2. Human Error Systematic Random
The experimenter does not know how to use the apparatus properly
The power of concentration of the experimenter is fading

3. Fix it! Systematic Random Calibrate/check the equipment often
Control as many other variables as possible to reduce these

4. Degrees of Precision ± half the smallest division on the instrument.
Ex: a thermometer whose smallest division is 1oC would measure
45o ± 0.5o

5. Unless it’s a mm ruler…..
± half the smallest decimal point measured to (place value with sig figs)
40.7 mm ± 0.5 mm
13 mm ± 5 mm
3.0 mm ± 0.5 mm

6. Or an electronic device….
Minimum uncertainty is ± one unit of the last decimal place (13.7 g ± 0.1 g)
Absolute uncertainty is in the literature for the device