Experimental+Uncertainty

*Page 34-36 on your textbook Experimental uncertainty: The experimental uncertainty is the estimated amount by which a measurement might be in error.
 * Experimental uncertainty **
 * __Definition:__ **

__** Key point: **__When an uncertainty is adding to a measurement, the uncertainty goes before the unit but after the measured value.

__ ** Example: ** __ Assume that there is a situation where a box of fruits is 17.6 Kg and the uncertainty in the measurement is Kg. So simply this situation can be shown as below:



__ ** Question ** __ ** : ** what if the uncertain digit is already in the first decimal place? A: If the uncertain digit is already in the first decimal place, then the uncertainty will also be in the first decimal place. Here I am going to use the example above to explain this point. In the example, the box of the fruits is 17.6 Kg and the uncertainty in the measurement is Kg, which means the actual value most lies in the range between (17.6+0.1)Kg to (17.6-0.1)Kg; that gives the answer from 17.7Kg to 17.5 Kg.
 * __Key Point:__**

__ **Question:** __ What if only the range of the possible of the values is known, in this case, it is 17.5Kg to 17.7 Kg , is given?

__ Answer: __ The uncertainty is just one half of the stated range.Range=17.7-17.5=0.2 Kg Uncertainty=0.5(0.2)=0.1Kg The measurement calculated is the midpoint of the range, plus or minus the uncertainty. The midpoint of the range is the AVERAGE of the endpoints of the range. Midpoint=0.5(17.5+17.7)=17.6Kg So the measurement should be 17.6Kg **__ Key Point: __** - The place of values of the experimental uncertainty and the first unertain digit of a measurement must agree with each other.

-Normally use uncertainties to the nearest 0.1 of the smallest unnumbered subdivision.

__Practice__: Page35 No 51-52

**__Link:__** More information about this topic : []

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