With a partner, try to complete the following conversions of our wonderful (??) English measurement system: 1 mile = ____________ yards 1 yard = ____________ feet 1 yard = ____________ inches 1 foot = ____________ inches 1 pound = ____________ ounces 1 cup = ____________ ounces 1 cup = ____________ tablespoons 1 tablespoon = ____________ teaspoons Water freezes at ____________°F Water boils at ____________°F

With a partner, try to complete the following conversions of the metric (SI) system: 1 km= ____________ m 1 m= ____________ cm 1 cm= ____________ mm 1 kg= ____________ g 1 L= ____________ mL 1 mL= ____________ cm 3 Water freezes at ____________°C Water boils at ____________°C

English vs. Metric Which of the two systems of measurement were the easiest to use? Why don’t you think that the United States hasn’t switched to the metric system like much of the rest of the world?

The Standard Metric Units The metric system is also referred to as the “International System” of units or SI (Standard International) Units The standard units of measurement that are used in the metric system are: For length: meter (m) For mass: kilogram (kg) For time: seconds (s) For temperature: kelvin (K) Add ° to °C to get K

Prefix multipliers The SI system uses prefix multipliers with the standard units of measurement (m,kg,s) These multipliers change the value of the unit by a power of 10 (Table 2.2, p. 23) – i.e. kilo means 1000 or 10 3 so 1 kilometer = 1000 meters

Prefix multipliers PrefixSymbolMultiplierExponential Form teraT1,000,000,000, giga G1,000,000, megaM1,000, kiloK1, Base: Meters Grams Seconds mgsmgs decid centic millim micro  nanon picop femtof hecto h deka da

deka 10 units 10 1 hecto 100 units 10 2 kilo 1000 units 10 3 deci.1 units centi.01 units milli.001 units grams Convert to kilograms: Move decimal 3 place to the left Or take 24g / 10 3 =.024 kg Convert to milligrams: Move decimal 3 place to the right Or take 24g x 10 3 = 24,000 mg

Practice Convert 2,156 g to the following units: – kg – Mg – mg – cg kg Mg 2,156,000 mg 215,600 cg

Derived Units Volume: Units of length to the 3 rd power become volume (cm 3, m 3 ) – length x width x height – water displacement We will commonly use liters to measure volume 1 mL = 1 cm 3 1 L = 1000 mL = 1000 cm 3

Derived Units Density: the amount of “stuff” crammed into something (a ratio of its mass to volume) density = mass volume ***This formula can also help you figure out mass and volume when given the other values

Volume/Density Practice What is the volume of a cube that has a width of 2.5 cm? – How many mL would that be? If the cube has a mass of 52.3 g, what is the cube’s density? If a copper penny has a density of 8.92 g/mL and a mass of 2.81 g, what is it’s volume? 15.6 cm mL d = m / v d = 52.3g / 15.6 cm 3 = 3.35 g/cm 3 V = m / d V = 2.81g / 8.92 g/mL = mL