Key science skills (KSS)

Controlled Experiment

A practical investigation that looks at the relationship between two variables.

Hypothesis

A prediction of the outcome of a practical investigation based on accurate scientific knowledge.

Independent variable

The factor, trait or condition changed by the scientist.

Dependent variable

Measurement made by the scientist; data collected due to the change in the independent variable.

Controlled variable

Factors that the scientist maintains as constant throughout the experiment.

Uncontrolled variable

A fault or change in an experiment that may introduce errors, typically experimental design issues.

Qualitative data

Data that is non-numerical and subjective.

Quantitative data

Data expressed as a number.

Primary data

Data collected by the investigator from first-hand sources.

Secondary data

Data collected from alternate sources such as literature reviews.

Accuracy

How close a result is to a standard or known true value.

Precision

How close two or more measurements are to each other.

Validity

A measurement is valid if it measures what it is supposed to be measuring.

Systematic errors

Errors that affect the accuracy of the data by causing a different reading from the true value.

Random errors

Errors that affect the precision of the data due to unknown variations.

Repeatability

The closeness of the agreement between results of successive measurements of the same quantity under the same conditions.

Reproducibility

The closeness of the agreement between results of measurements of the same quantity under changed conditions.