Chapter 1 - Objectives and Summary

LEARNING OBJECTIVES
Knowledge & Understanding

List the SI standard quantities together with their symbols, units and abbreviations.
Distinguish between a basic quantity and a derived quantity.
Convert from one unit to another.
List and classify the possible sources of errors encountered when making a measurement.
Find systematic and random errors. Calculate the error in an experiment.
Convert from exponential to decimal and vice versa.
Arrange a set of numbers in order of magnitude.
Use significant figures in calculations.
State simple error combination rules.

Scientific Techniques

Early measurements were based on body or heavenly features and differed from country to country.
There is an international system of units called SI which is most commonly used around the world and by scientists.
Measurable features or properties of objects are often called physical quantities. All physical quantities should be quoted with their numerical value and their unit.
Fundamental quantities (or base quantities) are those which are used to define all other quantities (derived quantities).
All measurements include errors or uncertainties, either systematic or random.
Powers of 10 are called exponential notation. Scientific notation includes exponents in the form M x 10ⁿ, where M is a number having a single non-zero digit to the left of the decimal point and n is a positive or negative exponent.
The order of magnitude is the power of 10 closest to to the number.
Significant figures are those digits in a number that are known with certainty plus the first digit that is uncertain.
Instruments used in measuring length include the ruler, the micrometer and the vernier calliper. Rotational speeds can be measured with a xenon stroboscope but there can be freezing' hazards.
Digital measurements in the on/off form can be taken with simple counters or computer interfaces.
Ideal measuring devices have no effect on the measurement itself.