Science Keyword

Science keyword for practical exam

Independent Variable

The variable for which the values are selected by the investigator. (the one you changed)

Dependent Variable

The variable for which the values change when the independent variable is changed. (the one you measured)

Controlled Variable

A variable which may affect the outcome of the investigation and therefore should be kept constant.

Range

The maximum and minimum values of the independent or dependent values. This should not be too big or too small.

Valid Conclusion

A conclusion supported by valid data, obtained from an appropriate experiment design and based on sound reasoning.

Validity of Experimental Design

Suitability of the investigation procedure to answer the question being asked. Strategies to ensure validity include fair tests and controls that aim to isolate the effect of the independent variable on the dependent variable.

Anomaly

Value in a set of results which is judged not to be part of the inherent variation.

Resolution

This is the smallest change in the quantity being measured by a measuring instrument that can be observed. For example ± 1mm on a meter ruler.

True Value

This is the value that would be obtained in an ideal measurement.

Uncertainty

The interval within which the true value can be expected to lie.

Measurement Error

The difference between a measured value and true value.

Systematic Error

These cause reading to differ from the true value by a consistent amount each time a measurement is made. Systematic errors can include the influence if the environment, the methods of observation or the instrument used. The effect of systematic errors cannot be reduced by increased repeats.

Accuracy

A measurement result is considered accurate if it is judged to be closed to the true value.

Precision

This shows the closeness of agreement between measured values. It gives no indication of how close results are to the true value.

Repeatability

The precision obtained when repeat readings are obtained by a single learner/group.

Repeatable

A measurement is repeatable, if repetition by a single learner/group using same method and equipment, obtains the same or similar results.

Reproducibility

The precision obtained when repeat readings are obtained by a different learners/groups.

Reproducible

A measurement is reproducible, if repetition by different learners/groups obtains the same or similar results. This could include using different equipment/ methods. This is a harder test of the quality of data

Hazard

A chemical or piece of apparatus that could cause harm. It is expected that in risk assessments the nature of the hazard is also specified.

Risk

An action involving a hazard that might result in danger.

Control measure

Something that can be done to reduce or prevent a risk while allowing you to carry out the experiment.

Random error

These occur due to results varying in an unpredictable way from one measurement to the next. The effect of random errors can be reduced by taking more measurements and calculating a mean.