dimensional analysis - idaho state · web viewdimensional analysis conversion factors si...

Dimensional AnalysisTeacher’s GuideBy: Rita Jones

Lesson Overview: The following lesson provides a powerpoint presentation to introduce the beginning concepts of dimensional analysis.

Subject area(s): Chemistry

National Science Education Standards Addressed:1. Dimensional Analysis2. Conversion factors3. SI Prefix Conversions

Topic: Dimensional Analysis

Audience: 9th-12th grade

Resources:1. Powerpoint inclusive2. Lemay, H. Eugene, Jr. Chemistry.

Prentice-Hall, Inc. 2002.

Suggested time: 55 minutes

Materials: Powerpoint software Calculators SI prefix conversion table

Learning Objectives:1. Students will be able to perform dimensional analysis.2. Students will learn how to use SI prefix conversion tables properly.3. Students will apply learning to actual problems.

Background:This is a fully prepared lesson plan which involves concept introduction and problems for the students to work on individually. This allows the instructor to walk around the classroom and help students who are struggling with the concept.

Assessment Strategy:The format of this lesson allows the instructor to assess whether the students are grasping the concept. If problems are seen in the students ability to work the problems individually, the instructor can work on it with them individually, or go back to the power point in order to reaffirm concepts.

Teaching tips:Students must work problems individually in order to fully grasp concepts.

Engage students by introducing concepts in the powerpoint and have students take notes on the information presented.

Have students explore their understanding by completing each problem individually.

Explain concepts by going through each problem as a group to make sure the student’s understanding is complete.

Extension(s):Additional worksheet should be given to each student as homework.

CH. 1CH. 1----MEASUREMENTMEASUREMENTIII.III. Unit ConversionsUnit Conversions(Sec. 1.7, pp. 38(Sec. 1.7, pp. 38--47)47)

Skills Check Skills Check

Multiplication of two integers Multiplication of two integers with exponents.with exponents.2222 x 2x 233 ==

2255

Division of two integers with exponents.Division of two integers with exponents.2277 ==

2233

2244

ProblemsProblems

335 x5 x 3322

3344

3333

4422

4455

114433

44--33

A. SI Prefix ConversionsA. SI Prefix Conversions

Use table on p. 937 to Use table on p. 937 to convert between convert between prefixes.prefixes.

Subtract the Subtract the exponents.exponents.

Move the decimal that Move the decimal that many places.many places.


1010--1212pppicopico--1010--99nnnanonano--1010--66μμmicromicro--1010--33mmmillimilli--1010--22cccenticenti--1010--11dddecideci--

101000------BASE BASE UNITUNIT

101033kkkilokilo--101066MMmegamega--FactorFactorSymbolSymbolPrefixPrefix

A.A. SI Prefix ConversionsSI Prefix Conversionspage 18page 18

SI units for mass:SI units for mass:grams (g)grams (g)

SI units for volume:SI units for volume:liters (L)liters (L)

SI units for length:SI units for length:meters (m)meters (m)

SI units for timeSI units for timeseconds (s)seconds (s)

SI units for temperature:SI units for temperature:kelvinkelvin (K)(K)

*It is important to know that when labeling units, upper *It is important to know that when labeling units, upper and lower case changes the meaning of the units.and lower case changes the meaning of the units.


532 m = ? km 532 m = ? km


1) 20 cm = __________ m1) 20 cm = __________ m

2) 0.032 L = __________2) 0.032 L = __________mLmL

3) 45 3) 45 μμm = __________ nmm = __________ nm

4) 805 dm = __________ km4) 805 dm = __________ km

B. Dimensional AnalysisB. Dimensional Analysis

The technique of converting between units is The technique of converting between units is called dimensional analysis.called dimensional analysis.

The The ““FactorFactor--LabelLabel”” Method.Method. Units or Units or ““labelslabels”” are canceled, or are canceled, or ““factoredfactored”” out.out.

cmcm33 x x g g = g= gcmcm33


Steps:Steps:1)1) Identify starting & ending units.Identify starting & ending units.2)2) Line up Line up conversion factorsconversion factors so units cancel. (p. so units cancel. (p.

38 and p. 936).38 and p. 936).3)3) Multiply all top numbers & divide by each bottom Multiply all top numbers & divide by each bottom

number.number.4)4) Check units & answers.Check units & answers.

*Stop to ask yourself: *Stop to ask yourself: ““Is my answer reasonable?Is my answer reasonable?””


Lining up conversion Lining up conversion factors:factors:

1 in 1 in = 1= 12.54 cm2.54 cm

1 = 1 = 2.54 cm2.54 cm1 in1 in


1) Your European hairdresser wants to 1) Your European hairdresser wants to cut your hair 8.0 cm shorter? How many cut your hair 8.0 cm shorter? How many inches will he be cutting off? (See p. 38 inches will he be cutting off? (See p. 38 and p. 936)and p. 936)


2) How many milliliters are in 1.00 quart of 2) How many milliliters are in 1.00 quart of milk?milk?


3) Taft football needs 550 cm for a 13) Taft football needs 550 cm for a 1stst

down. How many yards is this?down. How many yards is this?


4) You have 1.5 pounds of gold. Find its 4) You have 1.5 pounds of gold. Find its volume in cmvolume in cm33 if the density of gold is 19.3 if the density of gold is 19.3 g/cmg/cm33..


5) How many liters of water would fill a 5) How many liters of water would fill a container that measures 75.0 incontainer that measures 75.0 in33??


6) A piece of wire is 1.3 m long. How many 6) A piece of wire is 1.3 m long. How many 1.51.5--cm pieces can be cut from this wire?cm pieces can be cut from this wire?


Dimensional analysis can also be used to Dimensional analysis can also be used to convert using metric prefixes and convert using metric prefixes and exponents:exponents:

7) Convert 8470 s to 7) Convert 8470 s to μμs.s.


8) Convert 6.85 8) Convert 6.85 nLnL to to mLmL..


9) If I was traveling down the interstate at 9) If I was traveling down the interstate at 71 mph, what would this be in cm/s?71 mph, what would this be in cm/s?

dimensional analysis - idaho state · web viewdimensional analysis conversion factors si...

Documents