Errors, Uncertainties and Measurements Laboratory Report

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  • Topic: Measurement, Measuring instrument, Metrology
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Experiment 1: Errors, Uncertainties and Measurements
Laboratory Report

Abstract

The success of an experiment greatly depends on how the group is able to execute it and how precise and accurate their results are. In this matter, errors and uncertainties in measurements are of great factor. In this experiment, the group was able to classify the causes of such errors and which measuring device is more precise and accurate than the other. These were obtained by measuring the diameter of an iron sphere with several trials made by each member of the group using measuring devices such as the Foot Rule, the Vernier Caliper and the Micrometer Caliper. The group found out that in measuring, both the Vernier Caliper and the Micrometer Caliper are preferable to use for these can give more accurate measurements compared to what a Foot Rule can. The deviation, volume, mass and density of the iron sphere were also identified.

1. Introduction

Measurements may be ranked among the necessaries of life to every individual in the human society. The knowledge of them, as in established use, is among the first elements of education, and is often learned by those who learn nothing else, not even to read and write. Measurements were among the earliest tools invented by man. Primitive societies needed rudimentary measures for many tasks: constructing dwellings of an appropriate size and shape, fashioning clothing and bartering food or raw materials. Man understandably first turned to parts of his body and his natural surroundings for measuring instruments. As societies evolved, these practices seem to be unsuitable. Measurements became more complex. The invention of advanced measuring devices, numbering systems and the science of mathematics made it possible to create whole systems of measurement units suited to trade and commerce, land division, taxation, and scientific research. Some of these inventions are those that were used in the experiment conducted – Foot Rule, Vernier Caliper and Micrometer Caliper. In line with this, the group was tasked to meet its objectives which were to study errors and how they propagate in simple experiments; to determine the average deviation of a set of experimental values; to determine the mean of a set of experimental values as well as set of average deviation of the mean; to familiarize its members with the Vernier caliper, micrometer caliper and foot rule; to compare the accuracy of these measuring devices; and to determine the density of an object given its mass and dimensions. In a continuously evolving society, these improvements on the measuring devices and having accurate measurements would aid for success on various experiments scientists or even ordinary people may have, for the advancement of lives and for progress on any of the multifarious fields human beings may excel.

2. Theory

In physics, it is believed that every measurement has a degree of uncertainty. It means that there is no exact or correct measurement. The causes for these uncertainties are chopped down into 2 reasons: human and instrumental error. Human error can be identified as mistaken readings or conflicting readings among researchers. Instrumental error on the other hand, can be shown through their systematic, meaning that the instrument might have a malfunction or simply put, broken. With all this uncertainties, it was practiced to allow for an error but only for one half of a scale division. This means that for most instruments the total error for a measurement is ±1scale division. To aid in producing accurate answers the significant figures is used to lessen the doubtful figure to a lesser extent so that uncertainty can be subtracted into 1 significant figure. Though in using the significant figures, there are certain rules that should be followed in order to use it.

Rules:
1. When adding or subtracting two measurements the absolute uncertainties are added. If you multiply a measurement by a number you...
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