## Dimensional Analysis

A scary sounding name for something that is pretty darn easy.

### Why it ’s important to include your UNITS

• Units are essential to understanding data.

• A unit value.

gives definition to a numerical • 100 = number . 100 what? – The number alone does not tell us much.

• 100 kg is a quantity . – The unit gives us more information.

### Scientists speak METRIC !

- When scientists measure anything they use the metric system. - 3 basic units are: • Mass = Gram • Volume = • Liter or m Length = Meter 3

(Language Arts in Science, Crazy!!) The basic units can be further defined by adding a prefix.

• • • The main units we will use are: Kilo Centi Milli = 1000 = 1/100 = 1/1000

### Tools for Measure

• Mass= Scale • Volume= • Meter stick • Ruler • Graduated cylinder (displacement) • Length= • Meter stick • Ruler

### Converting Units

Dimensional Analysis a.k.a. Factor Labeling • We use proportions unit to another.

to convert from one • Some rules to remember: – Carry your units through the entire problem. Don ’ t lose them. – Use what you know or info that you are given (pg. 6 “Tools of a Scientist” binder packet) .

Example Problem : How many centimeters in 2 meters?

• We know how many meters. We want to know how many centimeters that is.

• Known fact: 1 m = 100 cm • Turn what you know into a ratio 2m X 100cm 1m = 200cm

### s Practice.

Work with a partner, then check with your table 1. How many grams in 5 kg?

2. How many centimeters in 6km?

3. How many millimeters in 1.5cm?

4. How many milliliters in 2.3 L?

5. How many meters in 16.4 km?

6. How many liters is 460 ml?