## Tuesday, November 29, 2011

### How To Succeed in Engineering: Dimensional Analysis and Tables

There have been too many instances where people in my engineering classes do NOT understand dimensional analysis or tables.  Sure, you may know how to do these things, but you need to be AWESOME at these things.  Some of you may not know what I'm talking about.  So let's have an introduction:

Dimensional Analysis
I’ve loved dimensional analysis since middle school!  When I was 13, I could recite a TON of conversions (shows you how nerdy I was).  Here are some examples:

Convert 12 miles to meters.

If you buy a sweater that is \$24, but 35% off, how much is the sweater?
Most people don’t know how to do these problems, at least not easily.

A dimension is a unit, which is like a number.  You can reduce the following: 5/5=1.  Well you can also do the following:  or  .

Think about other possibilities.  For instance,  .

Think about the unit actually represents.  Like area is just a two-dimensional length.  Volume is three-dimensional length.  Acceleration is the time derivative of speed which is the time derivative of length.  Okay, sure that was a little confusing.  But think about the bigger picture.  Here is a cool video to show you what I mean: Imagining the 10th Dimension.

TABLES
Now about half (yes ½) of my upper division thermodynamics class was spent teaching us how to read tables.  And still people failed that class.  Sure, thermo goes beyond reading tables, but if you can’t read a table accurately, you are going to make silly mistakes on your tests.  And tests are your entire grade!