02Post - SUSB-003 BACKGROUND Measuring devices have...

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1 Introduction to Laboratory Measuremen SUSB-003 Measurement SUSB SUSB-003 003 Last Updated: 9/7/2008 Measuring devices have intrinsic uncertainty i.e., limitations due to their design/construction scale, balance calendar, sundial, watch, USNO measuring cup, graduated cylinder BACKGROUND Uncertainty Measurement process itself may introduce additional uncertainty e.g., try to measure temperature of five drops of a warm solution with a cold laboratory thermometer Measurer usually plays a role in the measurement process reading a scale or liquid level, determining a quantity from a graph, describing the color of a solution BACKGROUND In chemistry, certain quantities are ft n h s n s fund m nt l Measurer/quantities often chosen as fundamental : l ength m ass, t ime (intervals), (area, volume), Many can be described in terms of these, e.g. Temperature Energy ml 2 /t 2 Velocity = l/t ; Electric Currrent; Some cannot, and require other fundamental quantities Many measuring devices are constructed so as to be LINEAR e.g. RULER : Distance between markings is the same everywhere on the ruler ANALOG CLOCK : angle change for 1 minute is the same ( 6 o ) around the entire dial RULE OF THUMB: On a LINEAR SCALE LINEAR SCALE , human eye is capable of estimating the location of a mark lying between two smallest divisions to the nearest 1/5 th of a division Linear/Rule UNITS AND DIMENSIONS What distinguishes scientific computation from arithmetic primarily is that most scientific numbers include units . / Bad news: calculators don’t generally keep calculators don t generally keep track of units. Good news: Proper attention to units by users often shows whether or not a calculation makes sense units PROCEDURE 1. Measure Diameter of Plastic Sphere 2. Weigh Plastic Sphere using two types of balance 3. Compute Density of Sphere using above two results & examine uncertainty 4.
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02Post - SUSB-003 BACKGROUND Measuring devices have...

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