AQA Science: Glossary - Calibration

Marking a scale on a measuring instrument. This involves establishing the relationship between indications of a measuring instrument and standard or reference quantity values, which must be applied.

For example, placing a thermometer in melting ice to see whether it reads zero, in order to check if it has been calibrated correctly.

e.g. Clive finds some old mercury thermometers, but the scales have worn off over the years. He doesn't want to throw them away as they appear to work very well. He decides to calibrate them.

Filling a beaker with ice and a little water, he lowers the thermometers into the mixture. Using a permanent marker, he marks a line on the thermometer to show the freezing point of water (0°C)

Clive then boils a beaker of water and places the thermometers into it. Again he marks the level of the mercury in the tubes (100°C)

Once cool, Clive carefully measures the distance between the marks, which is 20.0 cm.

1. If Clive wants to mark every 2°C on the thermometer, what will be the separation of the lines he needs to mark?
2. What assumption is made in calibrating a thermometer in this way?

 Accuracy Calibration Data Errors* Evidence Fair test Hypothesis Interval Precision Prediction Range Repeatable Reproducible Resolution Sketch Graph True Value Uncertainty Validity Valid Conclusion Variables* * These terms have a number of related items.

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