Physikalisch-Technische Bundesanstalt

What time, what length, what weight? Everything begins with time, length, weight – man is measured and his data are recorded immediately after he breathed for the first time. Starting with this very first breath, measurements accompany man throughout life: for the patient, the doctor makes a diagnosis (also) with the aid of measuring instruments; the athlete's achievements – how high, how fast, how far? – are determined by measurement. As consumers we have the goods and cloths measured – in the marketplace or at the petrol station; the energy consumed in the households is measured by gas, water and electricity meters. And as homo technicus who has recourse to technology in all situations of life, we trust in the measurements which made the production process possible at all. Measuring is something usual. Sometimes visible, usually invisible, but always omnipresent. Measurement technique is often felt to be "dull", "inaccessible" and "strange", but it has further, quite different aspects: it may be exciting, entertaining and close to everyday matters. "What is behind a blood pressure measurement?", "What is a dosemeter?", or "What has length measurement to do with lasers?" – in the following we will give (hopefully) enjoyable answers to these questions and to other questions concerning everyday measurements and the physical phenomena behind them.