Define uncertainty, Chemistry

Assignment Help:

This brings us to one thing that uniformly drives students crazy. When anything is measured in the lab, you must keep track of how accurately you can measure it. If you measure your licorice with a ruler, you can pretty easily tell how many centimeters long it is. With a little more effort, you can measure to the nearest tenth of a centimeter. One rule of thumb is that no matter how hard you try, you can only measure to the smallest division on your measuring instrument - in this case 0.05 cm with a ruler marked in tenths of cm, millimeters. This would mean that you are fudging and I will immediately know it if you tell me your licorice is 13.5762 cm long. You cannot measure closer than 13.55 0.05 cm with any accuracy with a standard wooden ruler marked in tenths of cm. It does not mean there is no possible way you can get a measurement with this many significant digits - you do need a better instrument to measure with though. In the following example we have claimed a slightly better accuracy than the rule of thumb given - this is as close as I would want to stretch it.

138_Uncertainty.gif

When you make more than one measurement of a length you are not changing the accuracy of your instrument (smallest division on your ruler) but you can change the precision of your measurement because by repeating the measuring process. When you carefully repeat a measurement several times, you are eliminating the possibility that, for example, you take a poor reading because you forgot to line up the end of the licorice with the 0 on the ruler well. So you are often encouraged to take measurements several times and average the results. Hint - if one measurement seems really different than what you might expect, try measuring it again. This is one of the quickest and least frustrating ways to catch errors in lab, hopefully before you leave for your next class.


Related Discussions:- Define uncertainty

Methods for manufacture of soaps, Methods for Manufacture of Soaps Ther...

Methods for Manufacture of Soaps There are the following three methods for manufacture of soaps: (a) The cold process (b) The hot process (c) Modern process

Electrochemistry, how to determine the ionic product of water?

how to determine the ionic product of water?

Determine the impurities of solids, Impurities of solids Impurities are...

Impurities of solids Impurities are frequently added to materials to improve the properties. For example, carbon added in small amounts to iron makes steel, which is stronger t

Organic chemistry, Alkyl halide on reaction with dry silver oxide

Alkyl halide on reaction with dry silver oxide

Combustion energy stored in a 1 litre bottle of propane, Compare the combus...

Compare the combustion energy stored in a 1 litre bottle of propane and butane. Suppose that the product temperature is 100°C. The density of liquid propane is 0.493 g cm -3

Energy required to dislodge electron h- atom, The energy required to dislod...

The energy required to dislodge electron from excited isolated H-atom, IE 1 = 13.6 eV   is: (1) = 13.6eV                        (2) > 13.6eV        (3) 3.4 eV

ATOMIC STRUCTURE, CALCULATE THE MOMENTUM OF APARTICLEWHICH HAS WAVELENGTH ...

CALCULATE THE MOMENTUM OF APARTICLEWHICH HAS WAVELENGTH OF 2A

Explain classification of arches, Explain classification of arches accordin...

Explain classification of arches according to shapes raw a neat sketch of Flemish bond (1 brick wall and 1.5 brick wall thickness ).

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd