IME 322 Metrology and Precision Report #3 Direct, Indirect, and Comparative Measurement 12/04/2021 Submitted by: Mohamed Hamdy 120180001 to Dr. Mohamed Nassef Direct, Indirect, and Comparative Measurement Direct Measurement In this measurement approach the measured quantity is found directly by comparing it with the standard quantity, Figure 1. No mathematical calculations are involved in this method. It is not a very accurate measurement method since it depends to some degree on human inventiveness in judgment making. Figure 1: The physical balance directly measures the weight of the matter. Indirect Measurement The direct measurement gives the inaccurate results in most of the cases. Hence, the direct method is rarely preferred for measurement. In indirect method of measurement, the physical parameters of the quantity are measured by the direct method, and then the numerical value of the quantity is determined by the mathematical relationship. Example: The length, breadth and height of the substance is measured by the direct method and then by the help of the given relation the weight of the substance is known. Weight = Length X Breadth X Height X Density Comparative Measurement This method involves comparison with either a known value of the same quantity or another quantity which is function of the quantity to be measured, figure 2. The instrument, which provides such a comparison, is known as Comparator. Figure 2: Beam balance finds unknown mass by comparing it to a known mass. References 1. Comparative measurement. (2020, July 16). Retrieved April 11, 2021, from https://gaugehow.com/comparator-gauge/ 2.What are the methods of measurements? 19, K. (2018, May 05). Retrieved April 11, 2021, from https://circuitglobe.com/methods-of-measurements.html. 3.Classification of methods of measurements (metrology). (n.d.). Retrieved April 11, 2021, from https://what-when-how.com/metrology/classification-of-methods-of-measurements-metrology/.
