Using a sextent to get a bearing at sea.

Measurement – Technology makes it possible to measure things very precisely. Atomic clocks keep time to an accuracy of one millionth of a second per year. Lasers can measure distance to a millionth of a meter. A scientist’s most important tools are the ones used for measuring – telescopes, spectroscopes, microscopes, stethoscopes, radar, thermometers, corers, Geiger counters, scales, barometers. –Bill Nye, Episode 97

  • The mechanized clock, 15th century – It quantified time.
  • The Gregorian calendar, 1582 – Debugged the Julian calendar, jumping ahead 10 days to synchronize the world with the seasons
  • atomic clock – in the mid-1950s, the first reliable atomic clocks were constructed. In 1967, the second was redefined in terms of the electronic transitions of a cesium atom.

Measurement – the act or process of measuring; the specific size of something that is determined by measuring.

tools used in measurement

  • altimeter, anemometer, balance, barometer, clock, Geiger counter, hourglass, level, plumb, rule, ruler, scale, seismograph, spoon, stopwatch, tape measure, thermometer, timer, yardstick

units of measurement

  • acre, bushel, byte, calorie, carat, centimeter, cord, cup, day, decibel, degree, fathom, foot, gallon, gram, hectare, horsepower, hour, inch, kilohertz, kilometer, knot, league, light-year, liter, measure, megabyte, meter, mile, minute, mph, ounce, peck, pint, pound, quart, rod, second, tablespoon, teaspoon, ton, volt, watt, yard
  • engineered instruments – spectrometers, oscilloscopes, cameras, telescopes, interferometers, tape recorders, thermometers etc. and tools like clocks, scale that help in improving the accuracy, quality and utility of the information obtained from an observation.

descriptions of measurements

  • big, bright, close, cold, deep, dim, distant, empty, enormous, equal, equivalent, fast, few, heavy, high, hot, large, light, long, loud, low, many, massive, minute, narrow, quiet, scant, shallow, short, slender, slim, slow, small, tall, thick, thin, vast, wide

That’s engineering

  • Accuracy is a measure of how close a measurement is to the correct or accepted value of the quantity being measured.
  • Precision is a measure of how close a series of measurements are to one another. Precise measurements are highly reproducible, even if the measurements are not near the correct value.

Do It
Challenges for you to work on…

  • PhET Interactive Science Simulations (interactive simulations website) – simulations encourage quantitative exploration, offer measurement instruments including rulers, stop-watches, voltmeters and thermometers. Manipulate these interactive tools. Responses are immediately animated effectively illustrating cause-and-effect relationships. Multiple linked representations (motion of the objects, graphs, number readouts, etc.)

Learn more…