Laboratory Report

Jan Luke Mendoza, Alexis Vienne Munar, Paula Murakami, Giorla Joanne Negre

Department of Math and Physics

College of Science, University of Santo Tomas

Espana, Manila

Abstract

Throughout the experiment the main goal is to find out about the realities in taking measurements, that is, that there will always be an uncertainty for each acquired value. And to find out and recognize these uncertainties was handled in the experiment. Tools of measurement were also introduced to the students and principles for accurate measurement were tackled to educate the individuals on how to get measurements with the least percentage of error with uncertainties.

1. Introduction

Throughout history, man has made and used various tools for measuring. It evolved from using their body parts to using daily objects then in formulating specific tools for measurement. Along with these innovations came the credibility of each measurement. It was then called to as measurement uncertainties. In the later years, systems of solutions are made in order to justify measurements in terms of accuracy and precision. From these solutions can errors be also known and calculated, thus are also prevented and minimized in the process. Measurement uncertainty arises from the lack of knowledge of how sure or accurate a measurement is. This produces a non- negative variation of results which can be compared from a true and accepted value. Accuracy refers to how close a measurement is to its accepted and real value while precision is defined as how different separate measurements with unchanged variables are showing the same values of results. Speaking of errors in relation to measurements, there are two classified namely, random errors and systematic errors. Random errors are from either environmental or manual (from the tool used) factors. These are unexpected since these arise from technicalities of the environment and also of the tools used. Systematic errors are mainly from the tool. It may either be because the tool has problems functioning well or if the tool was used improperly. This experiment aims to give the students the opportunity to study errors and how they propagate in simple experiment. It determines the average deviation of a set of experimental values and determine the mean of a set of experimental values as well as set of average deviation of the mean. Its objective also covers the familiarization of the students with the vernier caliper, micrometer caliper and the foot rule. To compare the accuracy of these measuring devices and to determine the density of an object given its mass and dimensions are also recognized as the experiment’s goals and objectives.

2. Theory

When taking measurements, we always encounter numbers which not in their most precise and accurate measurement and in these situations, the rules on the significant figures apply. Significant figures are important especially in determining how accurate a measurement can be. It tells whether a digit tallied or written is accurate or is just simply estimated. Its use is to decrease the percentage of error that will be encountered in the future, especially when doing experimental activities. The rules on significant figures tell that zeros play important and varying roles. Non-zero digits are to be considered significant along with zeros between these non-zero digits. Propagation of errors occurs when there are factors occurring that affect the accuracy and precision of each measurement. Errors occur either from the one getting the measurement, or from the measurement tool’s specifications. Here is the formula used in this exercise in getting the % error in the measurements: {experimental value – experimental value} *100

Accepted value

% error =

Least count represents the most accurate measurement a device can determine. It is shown as the least difference of each of the lines or subdivision...