Chapter 3 Scientific Measurement 3.2 Units of Measurement 3.1 Using and Expressing Measurements 3.2 Units of Measurement 3.3 Solving Conversion Problems Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Abbreviated from the French name, Le Système International d’Unités Using SI Units SI Units Abbreviated from the French name, Le Système International d’Unités Based on metric system. Adopted in 1960. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Using SI Units From these base units, all other SI units of measurement can be derived (i.e., volume, density, and pressure) SI Base Units Quantity SI base unit Symbol Length meter m Mass kilogram kg Temperature kelvin K Time second s Amount of substance mole mol Luminous intensity candela cd Electric current ampere A Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Prefixes are used for very large and very small lengths. Using SI Units Units of Length SI unit: meter (m). Prefixes are used for very large and very small lengths. All metric units are based on multiples of 10. As a result, you can convert between units easily. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Commonly Used Metric Prefixes Using SI Units Commonly Used Metric Prefixes Prefix Symbol Multiplier Factor kilo k 1000 103 hecto h 100 102 deca da 10 101 ------ ----- Base Unit (meter, gram, liter, etc) deci d 0.1 10-1 centi c 0.01 10-2 milli m 0.001 10-3 King Henry Died By Drinking Chocolate Milk http://www.eamesoffice.com/the-work/powers-of-ten/ Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Volume - space occupied by matter Using SI Units Units of Volume Volume - space occupied by matter For a rectangular solid, V = L x W x H SI unit: cubic meter (m3) Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

A more convenient unit is the liter. Using SI Units Units of Volume A more convenient unit is the liter. Liter (L): volume of a cube that is 10 centimeters (10 cm) along each edge 10cm x 10cm x 10cm = 1000cm3 = 1L Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

A smaller, non-SI unit of volume is the milliliter (mL). Using SI Units Units of Volume A smaller, non-SI unit of volume is the milliliter (mL). 1mL = 1 cm3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Units of Mass Using SI Units Mass – a measure of the quantity of matter SI unit: kilogram (kg) 1 kg = mass of 1 L of liquid water at 4 deg C. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Weight - force that measures the pull on a given mass by gravity. Using SI Units Units of Mass Weight - force that measures the pull on a given mass by gravity. Weight of an object can change with location. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Density: ratio of the mass of an object to its volume. SI unit: kilograms per cubic meter (kg/m3) mass volume Density = Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Density This figure compares the density of four substances: lithium, water, aluminum, and lead. Increasing density (mass per unit volume) 10 g 0.53 g/cm3 19 cm3 10 cm3 3.7 cm3 0.88 cm3 1.0 g/cm3 2.7 g/cm3 0.88 g/cm3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Because of differences in density, liquids separate into layers. As shown at right, corn oil floats on top of water because it is less dense. Corn syrup sinks below water because it is more dense. Corn oil Water Corn syrup Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Densities of Some Common Materials Interpret Data Densities of Some Common Materials Solids and Liquids Gases Material Density at 20°C (g/cm3) Density at 20°C (g/L) Gold 19.3 Chlorine 2.95 Mercury 13.6 Carbon dioxide 1.83 Lead 11.3 Argon 1.66 Aluminum 2.70 Oxygen 1.33 Table sugar 1.59 Air 1.20 Corn syrup 1.35–1.38 Nitrogen 1.17 Water (4°C) 1.000 Neon 0.84 Corn oil 0.922 Ammonia 0.718 Ice (0°C) 0.917 Methane 0.665 Ethanol 0.789 Helium 0.166 Gasoline 0.66–0.69 Hydrogen 0.084 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Calculate how many seconds are in one year (assuming 365 days Temperature Scales Do Now: Calculate how many seconds are in one year (assuming 365 days in one year). Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Temperature: measure of how hot or cold an object is. Temperature Scales Temperature: measure of how hot or cold an object is. SI unit: Kelvin (K) Common unit: Celsius Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Note: with the Kelvin scale, the degree sign is not used Temperature Scales Note: with the Kelvin scale, the degree sign is not used Celsius Kelvin 100 divisions 100°C Boiling point of water 373.15 K 0°C Freezing point 273.15 K Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Temperature Scales One degree Celsius is equivalent to one Kelvin on the Kelvin scale. To convert between the temperature scales, K = °C + 273 °C = K – 273 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Converting Between Temperature Scales Sample Problem 3.7 Converting Between Temperature Scales Normal human body temperature is 37°C. What is this temperature in kelvins? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Converting Between Temperature Scales Sample Problem 3.7 Converting Between Temperature Scales Normal human body temperature is 37°C. What is this temperature in kelvins? K = °C + 273 = 37 + 273 = 310 K Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

END OF 3.2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.