Basic Laboratory Techniques
Hari D. Mandal, PhD.
1. To use common laboratory apparatus in measuring mass, length, volume, temperature, and density 2. To compute the accuracy and the precision of a set of scientific measurements 3. To apply the concept of significant figures in reporting correctly scientific measurements Materials and Equipment
Ruler, meter stick, 10 mL graduated cylinder, 50 mL graduated cylinder, small and large test tube, 50 mL and 150 mL beakers, 50 mL Erlenmeyer flask, digital top-loading balance, unknown liquids for density determination, irregular solids for density determination, safety glasses, Lab manual that was used for measurement. Introduction
The International System of Measurement (SI) is used worldwide and has been adopted as the official system of measurement by most countries. It is commonly called the metric system. Our traditional American/English system of measurement (miles, quarts, pounds) requires many conversion factors. Take length, for example – there are inches, feet, yards, rods, chains, and miles. The metric system is much different. It is based on standard units that can be easily converted by multiplying or dividing by factors of ten. Engineers and scientists most often use these standard metric units: the meter, for length; the gram, for mass (or weight); the liter, for volume; and the degree Celsius (or less often Kelvin) for temperature. In common English, we often use the terms “accuracy” and “precision” interchangeably, to indicate how “correct” an answer is. However, in science the two terms have different meanings. Accuracy is a measure of how closely an observation is to the “true” or “accepted” value. Precision is a measure of how closely a group of observations are to one another. For example, about a dartboard, “accurate” would be hitting the bulls-eye or center of the target; “precise” would mean that all of your darts hit the target close to one another,...
References: Chemistry: The Central Science 12th edition Laboratory Manual 2012 Brown et al.
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