In this page we will explore measurement: how to report a measurement, the difference between accuracy and precision, and how to keep precision in measurements.
Quantity and UnitA quantity is the property being measured.
A unit is the standard that the measurement is being taken in. Qualitative and Quantitative MeasurementsMeasurements can be described as being either qualitative or quantitative. Click the picture to go to a website that describes the difference and read the information below:
The difference between a qualitative and quantitative property can be found in the stem of the word. Qualitative is related to a quality or description. Quantitative is related to a quantity or number.
Significant FiguresSignificant figures (aka Sig Figs, aka a chemistry student's nightmare) are important in understanding the accuracy and precision of a measurement, but they can often be confusing to first year chemistry students. Again, I have devoted an entire page to understanding significant figures, click the button below to link to that page.
Scientific NotationScientific notation is a way of writing very large or very small numbers by multiplying a coefficient by a power of ten. I have a whole page devoted to scientific notation and how to perform operations with scientific notation, click the button below to link to the page.
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MeasuringClick on the button above to go to a community college website that gives you descriptions of accurate and precise measurements with some practice problems.
Accuracy vs. PrecisionClick the picture above for a brief description of the difference between accuracy and precision. Then try watching the video below:
Units, Conversions, and Sig FigsThe video below does a good job of reviewing the main topics of this unit. The beginning of the video makes mention to the weight of a kilogram, check out this video from the Weird page for some more background.
Factor Label MethodWe can convert between metric units using the Factor Label Method. Click the picture to go to a website that explain how to perform these conversions. Click the button below to get a review of how to convert using dimensional analysis.
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