Physics

Measurements and uncertainties

# Measurements in physics

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Measurements in physics

Fundamental quantities and units

- Understand and recall the
**seven fundamental quantities**used in the International System of Units (SI) – second, metre, kilogram, ampere, kelvin, mole, and candela. - Be aware that each fundamental quantity has a associated
**SI unit**: second for time, metre for length, kilogram for mass, ampere for electric current, kelvin for temperature, mole for number of particles, and candela for luminous intensity. - Recognise that
**derived units**are generated by combining the fundamental units, e.g. newtons for force (kg m/s²) or joules for energy (kg m²/s²).

Precision, Accuracy and Uncertainty

- Distinguish between
**precision**(how closely individual measurements agree with each other) and**accuracy**(how close a measurement is to the true value). - Understand that
**uncertainty**represents a range within which the true value is likely to lie, and is sometimes described as the precision of the equipment. - Reconstruct
**percentage uncertainty**by dividing the absolute uncertainty by the measured value and multiplying by 100.

Measurement Techniques and Tools

- Differentiate between the types of measurements taken in an experiment, including
**discrete**,**continuous**, and**categorical measurements**. - Highlight the range of
**measuring tools**, such as metre rules, vernier calipers, and micrometers, and their corresponding precisions. - Grasp how
**random vs systematic errors**can have different impacts on results and recognise ways to reduce these.

Significant Figures and Scientific Notation

- Implement the rules for counting
**significant figures**in a given number. - Round numbers according to the principles of
**significant figures**, appreciating that uncertainties should have a maximum of two significant figures. - Use
**scientific notation**to conveniently express very large or small numbers.

Graphical Representation of Uncertainties

- Identify
**error bars**on a graph as a basic visual indicator of the uncertainty of each datapoint. - Understand how to calculate the
**gradient**and its**uncertainty**of a line of best fit, incorporating uncertainties of individual measurements. - Interpret the
**y-intercept**of the best fitting line and its**uncertainty**.

Data Analysis

- Understand how to evaluate
**mean**,**median**, and**mode**as statistical descriptors of a dataset. - Recognise
**standard deviation**as a measure of dispersion of a dataset. - Perform
**propagation of uncertainties**when doing calculations involving multiple measurements.

The aim is to understand and apply these principles and techniques to represent, analyse, and interpret scientific measurement data effectively in Physics.