# Unit 1: Physics and Physical Measurement (5 hours)

Students will appreciate the range of orders of magnitudes handled by Physicists. They will learn the meaning of significant digits, and the importance of order of magnitude. They will practise making order-of-magnitude estimations. Students will learn that a quantity is a number multiplied by a unit, and they will learn how the S.I. units are structured. They will learn about the central role of uncertainty in experimental science, and they will practise processing uncertainties in both arithmetical and graphical contexts. They will distinguish scalar and vector quantities, and review and expand their skills in handling vector quantities.

#### Essential idea

Since 1948, the Système International d’Unités (SI) has been used as the preferred language of science and technology across the globe and reflects current best measurement practice.

## Learning Targets

#### SMEO

Global Citizens: Physics is universal. If we ever make contact with intelligent life beyond our own solar system, the only cultural elements we will have in common are Mathematics and Physics (plus, I concede, certain aspects of Chemistry). Learn Physics and you learn a worldview that can be shared with anyone, anywhere, provided only that they too have had the good fortune to learn Physics. Physics – the same Physics – is in daily use in every airport, every construction site, every hospital, every factory, every media centre… everywhere, regardless of any other belief professed by its users.

### 1.1 Range of magnitudes of quantities in our universe

• 1.1.1 State and compare quantities to the nearest order of magnitude
• 1.1.2 State the ranges of magnitude of distances, masses and times that occur in the universe, from smallest to greatest.
• 1.1.3 State ratios of quantities as differences of orders of magnitude.
• 1.1.4 Estimate approximate values of everyday quantities to one or two significant figures and/or to the nearest order of magnitude.

### 1.2 Measurement and uncertainties

• 1.2.1 State the fundamental units in the SI system.
• 1.2.2 Distinguish between fundamental and derived units and give examples of derived units.
• 1.2.3 Convert between different units of quantities.

### 1.2 The SI system of fundamental and derived units

• 1.2.1 State the fundamental units in the SI system.
• 1.2.2 Distinguish between fundamental and derived units and give examples of derived units.
• 1.2.3 Convert between different units of quantities.
1.2.4 State units in the accepted SI format.
• 1.2.5 State values in scientific notation and in multiples of units with appropriate prefixes. Uncertainty and error in measurement
• 1.2.6 Describe and give examples of random and systematic errors.
• 1.2.7 Distinguish between precision and accuracy.
• 1.2.8 Explain how the effects of random errors may be reduced.
• 1.2.9 Calculate quantities and results of calculations to the appropriate number of significant figures. Uncertainties in calculated results
• 1.2.10 State uncertainties as absolute, fractional and percentage uncertainties.
• 1.2.11 Determine the uncertainties in results. Uncertainties in graphs
• 1.2.12 Identify uncertainties as error bars in graphs.
• 1.2.13 State random uncertainty as an uncertainty range (±) and represent it graphically as an “error bar”.
• 1.2.14 Determine the uncertainties in the gradient and intercepts of a straight-line graph.

### 1.3 Vectors and scalars

• 1.3.1 Distinguish between vector and scalar quantities, and give examples of each.
• 1.3.2 Determine the sum or difference of two vectors by a graphical method.
• 1.3.3 Resolve vectors into perpendicular components along chosen axes.

The detailed curriculum can be consulted here.