In science classes, numbers are often used to describe a measurement.\u00a0 As a result, when we report a number, it almost always needs a unit.\u00a0Without the unit, it is often difficult (or even impossible) to figure out what a number means.\u00a0 As an example, if I told you I needed a small job done and promised to pay you 10, how can you decide whether or not to take the job?\u00a0Certainly, your interest in accepting my offer will be radically different if I\u2019m offering to pay you 10 cents rather than 10 dollars.\u00a0 But it is not even entirely clear whether I am offering to pay you a lump sum, say 10 dollars for completing the job, or I am describing a rate, like 10 dollars an hour.\u00a0Because I haven\u2019t given you the units that will go with the number 10, it is not clear what the dimensions of the number are.<\/p>\n
With this in mind, there are a handful of skills we need to make sure we are comfortable with when working with units.\u00a0 For starters, we need to make sure we always report a measurment with its appropriate unit so we can interpret a given value correctly.\u00a0 If I tell you I need you to travel a distance of 100,000, it matters greatly whether that distance has a unit of millimeters, and is therefore equivalent to 100 meters, or a unit of miles, and requires you to circle the earth roughly four times.\u00a0 Second, we need to be able to use units to determine the dimensions of a calculated quantity through the process of dimensional analysis.\u00a0 And lastly, we need to be able to convert from one unit to another.\u00a0 We will need to convert between units within the same unit system and from units in one unit system to another.<\/p>\n\n\t\t\t Candela Citations<\/h3>\n\t\t\t\t\t