1. You gain from accurate measurements

2. Eyes (seeing) Ears (hearing) Nose(smelling) Mouth(tasting) Skin (feeling) inaccurate!! NASK – WAARNEMEN VS METEN Senses 1 temperature thermometer time clock, stopwatch length ruler weight scales more accurate than senses!! Measuring instruments 2 Inaccurate: Accurate: Repeated measurements keep giving different keep giving the same values values. Accuracy 4 Imprecise: Precise: Measurements are not on Measurements are close to the actual value Precise 5 One measurement alone says nothing about accuracy or precision No. of measurements 3 examples Stopwatch testone measurement large Classic stopwatch test

3. Accuracy can depend on:  The accuracy of the measuring instruments.  The number of measurements.  The accuracy with which they are used.  The accuracy with which the researcher reads the instrument

4. Accuracy of measuring School ruler at 1 cmaccuracy ± 0.5 cm Metal ruler at 1 mmaccuracy ± 0.5 mm Caliper at 0.1 mm accuracy ± 0.05 mm

6. The accuracy depends, among other things, on the scale. The step size is a measure for dividing the scale.

7. Step of 0.5 0.1 You make a division of scale by dividing the distance between minimal and maximal values in equal pieces of logical value.

9.  3 cm is different to 3.0 cm  The value of 3 is rounded to a value between 2.5 and 3.49  The value of 3.0 is rounded to a value between 2.95 and 3.049