Testimonial  “I was a Wheeler High School student who dozed off while Mr. Lajeunesse taught us dimensional analysis in chemistry last semester. I never quite got the hang of it. It irritated me… all of those fractions. I never really liked fractions. Although my grades had been pretty high, I got a “D” in chemistry and I dropped out of school second semester. I started on drugs, and then crime to support my drug habit. I am now in jail. I won’t get out of prison until 2013, and even then my self image is permanently damaged. I attribute all of my problems to my unwillingness to learn dimensional analysis.” – Nick

The Evidence  Studies conducted at Wheeler High from 2004 – 2010 show that 100% of high school students who do not use and understand dimensional analysis are seriously insecure by their senior year. Damage done from this deprivation in the first 2 – 3 years of high school is probably permanent and cannot be overcome by learning the method later in life. We recommend mastering this skill before completing your junior year.

More Evidence  83% of students who went to their Senior Proms from 2004 – 2010 admitted that they enjoyed solving problems with Dimensional Analysis in order to impress and confuse their parents. Of the 17% who did not enjoy using dimensional analysis, 11% were home from their senior prom before 11 PM and the other 6% went to the prom without a date.

When is MY Way Better than Using Dimensional Analysis? 1. When you’re super-intelligent and enjoy solving relatively simple problems in the most complex manner. 2. When you’re tired of always getting the correct answers. 3. When you’re an artsy type who won’t be confined by the structure of DA. You like messy solutions scribbled all over the page in every which direction. 4. When you have no interest in going to the prom or making the soccer team, and you don’t mind being unpopular, unattractive, ignorant, insecure, uninformed, and unpleasant. I’m just sayin’!

Dimensional Analysis  What happens when you divide a number by itself?  What happens when you divide a unit by itself?  In both cases, you get the number 1.  Dimensional analysis involves multiplication and division.  Focus on cancelation of UNITS  Just another method of unit conversion

First- learn the metric prefixes   You should memorize: 3 base units or 1000 base units  Kilo 1 x 10 3 base units or 1000 base units  So 1 km = 1000 m  Centi 1 x base units or 0.01 base units  So 1 cm = 0.01 m OR 100 cm = 1 m  Milli 1 x base units or base units  So 1 mm = m OR 1000 mm = 1m  Be able to use a chart for the others!  On the chart, use 1 with the prefix. Use the other number with the base unit (L, m, g)

Conversion factors  To convert between units:  Figure out what CONVERSION FACTOR you need to perform your calculation  Conversion factors – take a definition and turn it into a fraction equal to one – for example:  There are 12 inches in 1 foot  12 inches or 1 foot 1 foot 12 inches

Examples of dimensional analysis Multiply across the top. Divide by whatever’s on the bottom

Examples of dimensional analysis  Convert 2.6 km to mm  First- what is the desired unit?  Answer- mm  Second- how to we get from m to mm?  We know that 1 km = 1000 m  We know that 1 m = 1000 mm  2.6 km( 1000 m )(1000 mm) = m 1 km 1 m