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Accuracy
How close a measurement is to the true or accepted value.
Chromatography
Separates components of a mixture based on (1) their solubility in a mobile phase (e.g. solvent) and (2) their adsorption (attraction/attachment) to a stationary phase (e.g. paper).
Dependent variable
The variable that is measured; it may change in response to the independent variable.
Distillation
Separates liquids (or a liquid from dissolved solids) using differences in boiling point.
Evidence
Observations and measurements that support, contradict, or refine a hypothesis or theory.
Experiment
An experiment is a controlled way to collect measurements so you can decide whether a claim is supported.
Filtration
A technique used to separate an insoluble solid from a liquid in a mixture (e.g. a suspension).
Hypothesis
A testable prediction or proposed explanation that can be checked using observations or experiments.
Independent variable
The variable the experimenter deliberately changes to see its effect.
Measurement
A value that combines a number and a unit to describe the size of a quantity (for example, 2.4 m, 15 g, 8 s).
Mole
The amount of substance that contains $N_A=6.022×10^{23}$ particles (atoms, molecules, ions, etc.).
Peer review
A process in which other specialists evaluate scientific work before publication, checking methods, reasoning, and originality.
Physical quantity
A physical quantity is a measurable property that is described using a numerical value and a unit.
Precision
How close repeated measurements are to each other (how consistent they are).
Reliability
Reliability is the extent to which repeated measurements give similar results.
Resolution
Resolution is the smallest change in a measurement that an instrument can detect.
SI unit
SI units are internationally agreed standard units used for scientific measurement.
Uncertainty
An estimate of the range within which the true value of a measurement is expected to lie.