For example the measurement of the nominal length of an

Last updated: 1/29/2023

For example the measurement of the nominal length of an object is obtained by inspecting the scale of the evice and by listing one estimated digi measurement device and collecting the value of the nearest marking plus an estimated digit As a rule of thum i e when no additional information is available as in this case the precision uncertainty of one individua measurement is calculated as half the smallest division on the scale of the measurement device i e the leas count divided by 2 The individual measurement must be reported as nominal length including the estimate digit precision uncertainty and the units of the measurement Based on this how would you report the length of the shock absorber shown below Assume that the graduation of the rulers is in inches 10 points Measurement 10 points Measurement Nominal Length Estimated Digit Units Nominal Length Estimated Digit Units Problem 2 20 points A graduated cylinder is used to measure liquid volume The standard Sl unit of measure is the milliliter mL When measuring volume in a Meniscus graduated cylinder pipet or buret place it on a flat surface and view the height of the liquid in the cylinder with your eyes directly level with the liquid see example at right This prevents making parallax reading errors The liquid will tend to curve downward due to superficial tension i e the curved interface between air and liquid This curve is called the meniscus Always read the measurement at the bottom of the meniscus The graduated cylinder will usually have larger markings that are numbered There are smaller markings in between the larger units called graduations not necessarily numbered as shown in the figure The number of graduations between numbered markings determines the least count It is important to determine the least count before you start measuring To find the least count subtract the values of any two adjacent labeled graduations and divide by the number of intervals between them For example a Subtract the values of two adjacent labeled graduations 15 mL 10 mL 5 mL b Divide the previous number by the number of intervals between the two adjacent labeled graduations 5 mL 5 1 mL Therefore each graduation i e the least count of the cylinder is 1 mL There are three graduated cylinders shown in the picture at right The graduated cylinder on the far left has scale markings that are 0 1 mL apart so it can be read to the nearest 0 1 mL Hence we can estimate a volume of 5 75 mL 0 05 mL note that 0 05 mL in 5 75 mL constitutes the estimated digit and 0 05 mL is the uncertainty which was calculated as half of the smallest division of the scale of the measurement device 0 1 mL 2 0 05 mL Based on this example what is the measurement of volume in the center and rightmost graduated cylinders shown in the pictu Precision Uncertainty Units Precision Uncertainty Units ME 3113 Laboratory Assignment 1 Measurement Devices Page 3 of 5 20