Measurement and uncertainty: multiples, repeats, means and errors sim
Measure a stack of paper and a coil of wire on a rule and divide, time one swing and then twenty by hand, repeat the timing until the spread shows, find and leave out a miscounted timing, work out the mean, range and uncertainty, then correct a balance and a newton-meter for their zero errors and read a thermometer at eye level instead of from above, and record it all with the right headings, precision and significant figures.
Physical quantities, units and measurement · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Model: a timing by hand = (swings × T) + (stop error − start error); each press error is random, a normal spread with σ = 0.06 s (chosen). Pendulum 25.0 cm long, moved by T = 2π√(L/g) with g = 10 N/kg (beyond the syllabus; it only moves the bob and sets the light gate). Paper 0.104 mm a sheet (chosen); 28 s.w.g. wire 0.376 mm. Millimetre rules read to half a division (0.05 cm); stopwatch to 0.01 s; balance to 0.1 g; newton-meter 0 to 2.5 N in 0.1 N divisions; thermometer −10 to 110 °C in 1 °C divisions. Idealised: identical sheets and touching turns; a steady swing; the light gate exact; a balance and newton-meter whose only error is the zero error; parallax from a 2 mm gap between the column and the scale.
- The part being measured at this station
- Rules, retort stands, light gate, stopwatch, balance, newton-meter, thermometer
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