Topic 1: Measurement and uncertainties (5 hours) Essential idea: Since 1948, the Système International d'Unites (SI) has been used as the preferred language of science and technology across the globe and reflects current best measurement practice. 1.1 Measurement in Physics Understandings: . Fundamental and derived SI units . Scientific notation and metric multipliers · Significant figures · Orders of magnitude · Estimation Order of magnitude Applications and skills: . Using SI units in the correct format for all required measurements, final answers to calculations and presentation of raw and processed data . Using scientific notation and metric multipliers · Quoting and comparing ratios, values and approximations to the nearest order of magnitude · Estimating quantities to an appropriate number of significant figures
Order of magnitude of some masses Order of magnitude of some lengths Order of magnitude of some times MASS grams Electron 10-27 Proton 10-24 Virus 10-16 Amoeba 10- Raindrop 10-3 Ant 10º Human being 105 Pyramid 1013 Earth 1027 Sun 1033 Milky Way galaxy 1044 The Universe 1055 LENGTH meters Diameter of proton 10-15 Diameter of atom 10-10 Radius of virus 10-7 Radius of amoeba 10-4 Height of human being 10º Radius of Earth 107 Radius of Sun 109 Earth-Sun distance 1011 Radius of Solar System 1013 Distance of Sun to nearest star 1016 Radius of Milky Way galaxy 1021 Radius of visible Universe 1026 diameterof a nucleus 1. The ratio diameterof an atom is approximately equal to 1. 10-15 B. 10-8 . C. 10-5 . D. 10-2 . 2. The diameter of the nucleus of a hydrogen atom is of the order of A. 108 m. B. 10-15 m. C. 10-23 m. D. 10-30 m TIME seconds Light passing across a nucleus 10-24 Time period of red light wave 10-16 Time for one cycle of a supercomputer processor 10-1? Light travels 30cm 10" Blink of an eye 10 One second 109 One hour 103 One day 10€ One month 106 One year 107 The age of the universe 101 (1) (1) 3. The number of heartbeats of a person at rest in one hour, to the nearest order of magnitude is A. 101. B. 102 . C. 103 . D. 4. The diameter of a proton is of the order of magnitude of 105. (1)
A. 10-12 m. B. 10-15 m. C. 10-18 m. D. 10-21 m. (1) 5. The time interval between human heartbeats is of the order of A. 10-2 s. B. 10" s. C. 10º s. D. 101 s. (1) 6. The order of magnitude of the weight of an apple is A. 10-4 N. B. 10-2 N. C. IN D. 102 N. (1) 7. Sub-multiples of units may be expressed using a prefix. Which one of the following lists the prefixes in decreasing order of magnitude? A. centi- micro- milli- nano- B. milli- centi- nano- micro- C. centi- milli- micro- nano- D. milli- micro- centi- nano- (1)