CHEMISTRYSEPT 10, 2014

DIMENSIONAL ANALYSIS BASIC

SCIENCE STARTER

•Define measurement•What is the difference

between quantitative and qualitative data?

OBJECTIVES

• SWBAT applied dimensional analysis

AGENDA

• SCIENCE STARTER• DIMENSIONAL ANALYSIS APPLICATION

EQUIVALENT RELATIONSHIP

• 1 cake = 4 slices of cake–So, 1 cake or 4 slices of cake is

the same amount of cake.–So, this ratio is equal to one

another

CAKE EXAMPLE

• How many slices of cake do you have if you have 2 cakes?

CAKE MATH

Dimensional analysis

• Converting a given unit into another unit

Dimensional analysis

• A = What is given (include an amount and a unit. E.g., 2 inches)• = the equivalent relationship.– with C being the amount with the

same unit as A• D = answer in the desired unit

Example

• Cake Example – How many slices of cake do you have if you have 2 cake? Equivalent relationship: 1 cake = 4 slices

EXAMPLE

• Convert 2 feet into inches–Equivalent relationship = 1 foot

= 12 inches

Step 1: Identify what you know

• A = 2 feet• C = 1 foot• B = 12 inches• D = ______ inches (unknown

amount)

Step 2: Identify the equivalent relationship(s)

• 1 foot = 12 inches

Step 3: Set up the dimensional analysis equation

Step 4: Cancel out the similar units located on opposite side of one another

Step 5: Do the math

KIT KAT EXAMPLE

• What happens when you need to use more than one Equivalent Relationship.

• Let’s look at the KIT KAT EXAMPLE.

KIT KAT EXAMPLE

DEMONSTRATE LIVE EXAMPLE

MULTIPLE EQUIVALENT RELATIONSHIPS

• Many time, you may have to use multiple equivalent relationships to get to the final unit you want.

DIMENSIONAL ANALYSIS FOR MULTIPLE EQUIVALENT RELATIONSHIP

Dimensional analysis

• A = What is given (include an amount and a unit. E.g., 2 inches)

• = the equivalent relationship.– with C being the amount with the same unit as A

• = the equivalent relationship.– with E being the amount with the same unit as B

• Z= answer in the desired unit

KIT KAT EXAMPLE

• How many pieces of Kit Kat do you have if you bought 5 bags?

KIT KAT EQUIVALENT RELATIONSHIPS

• 1 bag = 21 Kit Kats.–So, this ratio is equal to one

another• 1 Kit Kats = 2 pieces–So, this ratio is equal to one

another

PRACTICES

• WORK ON THE PRACTICE PROBLEMS• YOU HAVE 10 MINUTES

EQUIVALENT RELATIONSHIPS

• 1 FT = 12 INCHES• 1 FT = 0.3048 M• 1 M = 100 CM• 1 G = 100 CG• 1 KG = 1000 G• 1 MIN = 60 SEC• 1 HR = 60 MIN