Physical properties

Physical properties

Properties we can observe and measure

precise

Getting the same result/number over and over again.

accuracy

closest to the real value

error

The difference between the measured value and the “true value” of the thing being measured. They can be known and corrected.

uncertainty

A quantification of the doubt about the measurement result.

independent variable

What you change.

dependent variable

What you see changing.

controls

Constants. What you keep the same to ensure a fair test.

Resolution

The smallest change that can be measured by a piece of equipment.

You can only make measurements to the same accuracy as…

the resolution of the piece of equipment that you’re using.

The uncertainty in a reading is usually the same as…

the resolution of the equipment used.

random error

An error caused by factors that vary between readings.

• Brought about by things out of your control

• Reduce to improve precision

• Can be reduced by repeating readings

systematic error

An error that causes every reading to be different from their true values by the same amount.

• Brought about by measuring equipment

• Reduce to improve accuracy

• Can be reduced by calibrating instruments

zero error

A systematic error caused by equipment not being calibrated or ‘zeroed’ before measuring.