Importance of Measurement


Mathematics plays an important role in the sciences, from making physical observations about the size of objects to describing how objects operate to predict what they may do in the future. In this course, we focus on being able to use mathematics to describe how much of something is present, generally in a reaction. This involves some kind of measurement.


Measurements consist of two things, a number and a unit. One without another has no meaning. For example, say a patient takes 600 calcium supplements with the intention of better bone health. But how much is 600? How does it compare with what's recommended for the patient's diet? Only knowing that the patient is taking 600 doesnt help answer this question. A unit is needed.


Here is a video explaining the differences between the US Customery system you've grown up using with common units used in the metric system.




Scientists and medical professionals use the metric system as the standard system of units. This is because the powers of 10 are easy to convert between. The prefixes for these have to be memorized as well as their associated powers of ten. You must also develop a feel for their relative size, which will make applying them during calculations much easier.


The following table shows some of the common metric relationships used in your field.


Table 2.2.jpg



Notice how all the relationships start with a base unit or reference point and build from that point. The base unit is always 1 and some metric unit. The prefix is then added to adjust the size of the base unit, for handling bigger or smaller numbers. Prefixes with the base unit multiplied by positive powers of ten are larger than the base unit. For example, kilo is made up of 1,000 of the base unit, or 103.



1kilometer = 103 m


1meter, the base unit


1milliimeter = 10-3m


1centimeter = 10-2m


1micrometer = 10-6m


1nanometer = 10-9m



Where is 101.



Quite simply, you have to memorize these relationships between the powers of ten for the metric system. Heres a set of flash cards to help get you started.



learning activity Convert the term to other metric units, including kilometer, meter, centimeter, millimeter, micrometer, and nanometer. Click ‘Show’ to see the hidden portion and check your answer.
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Play a game of mahjong while helping you recall your metric prefixes. Make sure you change the "Game" to "Metric Prefixes" and hit "New Game" when you are ready to start.



Heres an activity to help practice the scale of the metric prefixes.



learning activity Drag items from the left column to the right in order of decreasing size, largest at the top, smallest at the bottom.
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