Experiment 1 Rulers vs Calipers In this experiment you will compare the precision and accuracy measuring the same objects with a ruler and a caliper Materials 1 Marble Ruler String 1 8 oz Styrofoam Cup Vernier Caliper 1 Washer Procedure 1 Using the ruler measure the diameter of the marble Record your measurement in Table 1 2 Indicate your uncertainty Record the uncertainty in Table 1 3 Repeat Steps 1 and 2 for the outer diameter of the washer inner diameter of the washer washer thickness length of the string and the height of the Styrofoam cup 4 Repeat Steps 1 3 using a Vernier caliper Table 1 Ruler and Caliper Measurements Ruler Object Marble Diameter Measurement cm Uncertainty cm Caliper Measurement cm Uncertainty cm 1 0 cm 0 05 cm 1 22 cm 0 0025 Washer Outer Diameter 1 8 cm 0 05 cm 1 41 cm 0 0025 Washer Inner Diameter 0 8 cm 0 05 cm 0 63 cm 0 0025 0 1 cm 0 05 cm 0 12 cm 0 0025 609 6 cm 0 05 cm 609 4 cm 0 0025 Washer Thickness String Length 2014 eScience Labs LLC All Rights Reserved Styrofoam Cup Height 8 6 cm 0 05 cm 8 71 cm 0 0025 Post Lab Questions 1 Compare the measurements for objects using the ruler and caliper and write a general statement on when it is more beneficial to use a ruler rather than a caliper It is more beneficial to use a caliper than a ruler because the caliper demonstrates a more precise measurement and a smaller uncertainty value 2 Comment on accuracy vs precision for rulers and calipers Calipers will demonstrate a more precise measurement because rulers only extend two decimal places where as calipers extend 3 Calipers are generally more accurate than rulers as well because both a major and minor scale is used in determining the measured value Rulers rely on plain eyesight for measurements and result in less accurate data 3 What are the sources of uncertainty when using a ruler and caliper Ensuring the jaws of the caliper are perfectly aligned within the boundaries of what is being measured the variation in materials flat v round surface calibration of instruments eyesight Ruler zero line on the ruler not aligning with the starts measurement point when measuring the diameter the ruler might not be in the exact center of the object eyesight does not always give most correct measurement Caliper object may not be centered risk inaccurate reading due to misalignment of the major and minor scales 2014 eScience Labs LLC All Rights Reserved
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