1-1 Physical quantities, standards and units What will be measured? Physical quantities: mass, length, time, force What's the standard for a measurement? Maintaining and developing standards is an active branch of science Units There are seven kinds of base units in SI system1-1 Physical quantities, standards and units • What will be measured? Physical quantities: mass, length, time, force… • What’s the standard for a measurement? Maintaining and developing standards is an active branch of science. • Units There are seven kinds of base units in SI system