Dimensional Analysis
 Charts, instructions and worksheets are at the bottom of this page.
The story ...  I graduated with a dual degrees in geology and math from Sul Ross State University that is beautifully built on the side of a mountain in Alpine, Texas.  Alpine is in far West Texas about 160 miles South West of Midland, about 225 miles Southeast of El Paso, about 300 miles West from San Antonio and 80 miles North of Big Bend National Park. Early one Saturday morning four of us in the geology department drove to Chihuahua City, Mexico to purchase some mineral samples for our department's lab. Our driver behind the wheel of an old Blazer was attempting to drive at break neck speeds over these not-so-good roads in Mexico. We passengers became a bit worried with Carl's driving and this is an "edited" portion of a conversation that ensued ...

"Dude! Are you trying to kill us? Why are you driving so fast?" one of us screamed!
Carl, the driver replied, "Man, I am only trying to do that speed limit."
"Speed limit, you're WAY OVER the speed limit!" someone shouted.
"What do you mean over the speed limit, that sign back there said 95," Carl replied.
"You idiot! That sign was 95 kilometers per hour, not 95 miles per hour," all of us ruthlessly yelled.

Carl thought that 95 km/h was Spanish for 95 mph! He didn't know his dimensional analysis!

This dimensional analysis mistake cost $125 MILLION!
In January of 1999 NASA launched a weather satellite to be placed into orbit around Mars. The name of the satellite was the Mars Climate Orbiter. The wrong system of units used in the calculations caused this mission to end in failure. Below are several exerts from articles as to what happened.

"The 'root cause' of the loss of the spacecraft was the failed translation of English units into metric units in a segment of ground based, navigation related mission software, as NASA has previously announced," said Arthur Stephenson, chairman of the Mars Climate Orbiter Mission Failure Investigation Board.
ref: http://sse.jpl.nasa.gov/news/display.cfm?News_ID=232

"NASA lost two missions to Mars in 1999, which included an orbiter that burned up in the Martian atmosphere because of a mix-up of English and metric propellant measurements."
ref: http://www.cnn.com/2003/TECH/space/07/08/mars.rover/

 In a preliminary report, JPL said the spacecraft's builder, Lockheed Martin Astronautics, submitted acceleration data in English units of pounds of force instead of the metric unit called Newton's. At JPL, the numbers were entered into a computer that assumed metric measurements.
ref: http://www.canoe.ca/CNEWSSpace9910/01_metric.html

  Below are listed charts and worksheets for the dimensional analysis unit. All of these notes have been converted to Adobe's PDF. If you don't already have Adobe's Acrobat reader, click on the icon below to download and install it, it's free.

Metric Conversions Chart
How to do that unit conversion
Dimensional Analysis Worksheet
 Scientific Notation Worksheet
Significant Figures Worksheet 
Great Sig-Figs tutorials: http://www.chem.sc.edu/faculty/morgan/resources/sigfigs/index.html
Sig-Figs on-line practice: http://antoine.frostburg.edu/chem/senese/101/measurement/sigfig-quiz.shtml