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  2. Analytical balance - Wikipedia

    en.wikipedia.org/wiki/Analytical_balance

    Before using a triple beam balance, the scale pointer should be at zero. [6] The zero adjustment knob can be used to adjust the scale pointer. Place the objects on the pan and adjust the riders until the scale pointer is at zero again, and then sum the weights marked (e.g. the 4th notch of 100 gram beam is 400g) to find the weight of the sample.

  3. Ab initio quantum chemistry methods - Wikipedia

    en.wikipedia.org/wiki/Ab_initio_quantum...

    The Hartree-Fock (HF) method scales nominally as N 4 (N being a relative measure of the system size, not the number of basis functions) – e.g., if one doubles the number of electrons and the number of basis functions (double the system size), the calculation will take 16 (2 4) times as long per iteration.

  4. Accuracy and precision - Wikipedia

    en.wikipedia.org/wiki/Accuracy_and_precision

    Accuracy is also used as a statistical measure of how well a binary classification test correctly identifies or excludes a condition. That is, the accuracy is the proportion of correct predictions (both true positives and true negatives) among the total number of cases examined. [10]

  5. Baumé scale - Wikipedia

    en.wikipedia.org/wiki/Baumé_scale

    The Baumé scale is a pair of hydrometer scales developed by French pharmacist Antoine Baumé in 1768 to measure density of various liquids. The unit of the Baumé scale has been notated variously as degrees Baumé, B°, Bé° and simply Baumé (the accent is not always present). One scale measures the density of liquids heavier than water and ...

  6. Calibration - Wikipedia

    en.wikipedia.org/wiki/Calibration

    The formal definition of calibration by the International Bureau of Weights and Measures (BIPM) is the following: "Operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties (of the calibrated instrument or ...

  7. Calibration curve - Wikipedia

    en.wikipedia.org/wiki/Calibration_curve

    A calibration curve plot showing limit of detection (LOD), limit of quantification (LOQ), dynamic range, and limit of linearity (LOL).. In analytical chemistry, a calibration curve, also known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. [1]

  8. Vernier scale - Wikipedia

    en.wikipedia.org/wiki/Vernier_scale

    Vernier caliper scales; main at top, vernier at bottom. It reads 3.58 ± 0.02 mm by adding 3.00 mm (left red mark) on the fixed main scale to vernier 0.58 mm (right red mark). The main scale reading is that to the left of the zero on the vernier scale. The vernier reading is found by locating the best aligned lines between the two scales.

  9. Approximation error - Wikipedia

    en.wikipedia.org/wiki/Approximation_error

    In most indicating instruments, the accuracy is guaranteed to a certain percentage of full-scale reading. The limits of these deviations from the specified values are known as limiting errors or guarantee errors. [6]