Children who are taught at the earliest levels in mathematics and science will not grow up innumerate and with hopeless fear of science

Leon Ledermann, chairman of the International
Council of Scientific Union Committee
On Capacity Building in Science, USA
GIREP Newsletter, April 1995

The SI system of measurement was established in 1960 and since then it has been the most widely used system by scientists, engineers, technicians and businessmen all over the world. In science we deal with the measurement of various quantities of very different dimensions, from the smallest particles of atoms, through everyday dimensions to the gigantic distances between planets, stars and galaxies. 

In order to make an acceptable measurement, solve a textbook problem or a technical problem, students, technicians or engineers should have the ability to manipulate numbers expressed in the power of ten notation, an idea of the expected quantities that will result, and basic familiarity with the SI units and prefixes and often with appropriate uncertainties. 

They should be also acquainted with conversion of units within the SI system and often between the SI system and the British (imperial) fps system that is still in use in the UK and USA. Despite the universal adoption of the SI system of measurement, students in many countries leaving secondary school, whether for further technical training, university or work, are inadequately prepared in the application of the system. This is also noticeable in US factories manufacturing products for export.

Many science textbooks still in use in secondary schools content themselves only with a sketchy introduction to the SI system. This book is written for students in secondary schools, in technical and teacher-training colleges as well as students starting degree courses in the physical sciences as an addition to core physics textbooks.