Dimensional Analysis for Conversions

Write the KNOWN, identify the UNKNOWN.

EX. How many quarts is 9.3 cups?

9.3 cups ? quarts=

Write the KNOWN, identify the UNKNOWN.

EX. How many quarts is 9.3 cups?

9.3 cups ? quarts=

Draw the dimensional “jumps”.

9.3 cups ? quarts=

9.3 cups x

* Use charts or tables to find relationships

Insert relationship so units cancel.

9.3 cups xcups

*units of known in denominator (bottom) first*** units of unknowns in numerator (top

quart

4

1

Cancel units

9.3 cups xcups

quart

4

1

Do Math

9.3 cups xcups

quart

4

1

•Follow order of operations! •Multiply values in numerator•If necessary multiply values in denominator•Divide.

Do the Math

9.3 cups xcups

quart

4

1

1 x 4

=9.3 x 1

4=

9.3= 2.325 quarts

Try this:

1.How many seconds are in 6 minutes?

____ seconds(6o seconds = 1 minute)

2.How many centimeters are in 27 inches?

____ centimeters(1 inch = 2.54 centimeters)

Metric Conversions Ladder Method

T. Trimpe 2008 http://sciencespot.net/

Why do we need units of measurement?

If I tell you that I weight 200, it will make a difference whether it is pounds or kilograms.

Kilograms are 2.2 times heavier than a pound!

Systems of Measurement

The English system was based on the King’s measurement.

Inch was based on the width of his thumb Feet were the length of one foot Yards were the circumference of the king’s waist

But what happens when the king dies and his son’s measurements are LARGER?

International System of Units (SI units)

Metrics are used by SCIENTISTSBased on standardized measurementsUsed worldwide. Based on multiples.

KILO1000Units

HECTO100

UnitsDEKA

10Units

DECI0.1

UnitCENTI

0.01Unit

MILLI0.001Unit

MetersLitersGrams

Ladder Method12

3

Try these conversions using the ladder method.

1000 mg = _______ g 1 L = _______ mL 160 cm = _______ mm

14 km = _______ m 109 g = _______ kg 250 m = _______ km

Conversion Practice

Compare using <, >, or =.56 cm 6 m 7 g 698 mg

Write the correct abbreviation for each metric unit. Kilogram _____ Milliliter _____ Kilometer _____

Meter _____ Centimeter _____ Gram _____

Liter _____ Milligram _____

Try these conversions..2000 mg = _______ g 5 L = _______ mL 16 cm = _______ mm104 km = _______ m 198 g = _______ kg 2500 m = _______ km

Metric Conversion Challenge