MEASUREMENTS Data and Observation: METRIC SYSTEM Width Thickness (cm) ENGLISH SYSTEM Width (in) 0-1.54 Objective: To understand the relationship between the construction of a measuring Length (cm) Length (in) Thickness (in) Trial (cm) 0-3.85 instrument. 0-6.71 0-1.50 0-2.62 0-.56 Apparatus: Meter stick or ruler ( English and Metric scale ), rectangular wooden block, 1-4.90 1-2.50 1-2.53 1-7.72 1-3.63 1-1.57 3-9.70 3-6.80 4-5.50 2-4.63 2-3.52 2-2.58 Theory : Since Physics is a science based on measurements, familiarity with common measuring instruments is necessary. A measurement taken from a body or from an object must have a corresponding number and unit. Unit involves three fundamental concepts - length, mass and time- and all the rest can be derived from these showing the unity of Physics. Ave 6.71 3.85 1.50 2.63 1.53 0.57 Volume of the block in cm (average) cm Votume of the block in inch (average) inch %3D Therefore, I inch cm Accepted value (AV) The simplest method in measuring the length, the width and the thickness of object is the use of meter stick or ruler. The smallest accurate reading that can be obtained from the meter stick or ruler s 0.1 cm on the CGS scale and 1/8 in. on the English scale. Inaccurate measurement occurs when estimating the fraction of the smallest division. To minimize error in measurement, smallest reading must be taken. Percentage Eror 1 in' = 16.39 cm? Computation and Analysis: Procedure: 1. Measure the length, width and thickness of the rectangular wooden block at some intemediate mark in centimeters and in inches. Record you: readings. Repeat the measurement but this time, start the measurement at a different mark on the meter stick or ruler. Make at least three trials. The reading at the mark with which you start must be subtracted from the final reading. Record all your readings. The average of the three readings will be considered as the most probable value. 2. Compute the volume of the block (Volume = length x width x thickness ) on Metric and English scales. From these values, find out how many centimeters make an inch, accurate to second decimal places. Determine the percentage error. Conclusion: