Reliable ––- Errors

Readings should be repeated to identify anomalies and thus increase reliability

Errors

• human error problems with our own human fallibility

• systematic error problems with the system of measurement and/or the equipment

• random errors inconsistencies in the way the measurements are done

Try this experiment to measure TIME

Drop a cake case once and once only from a height of 100cm and time how long it takes to fall.

You are not allowed to practice !

Record your value:

t = s +/- ( Sig Figs)

Questions …. To be answered in full sentences:

• is this result reliable, and why ?

• is this result valid, and why ?

• what kind of errors are you likely to have in this measurement?

Improved Experiment:

Describe how you could make the reading more reliable

• Carry out the method you have suggested.

• Draw up a table to show all your readings.

• State a reliable value for the time to fall 100cm.

• Is your reliable value a valid value, and why?

Extension if time:

Refer to your “How science works” sheets … what kind of variable is

• height

• time

Apparatus: metre rule, stopclock, cake case.