1. 21-May-15 Physics 1 (Garcia) SJSU Chapter 12 Solids (Just the section on “Density”) Part II: Properties of Matter

2. 21-May-15 Physics 1 (Garcia) SJSU Demo: Iron and Cork What is heavier, iron or cork? Depends on how much you have. A big bag of cork can weigh more than a small iron nail. Think of iron as being heavier because it is heavier for the same volume. Small iron nail BIG BAG OF CORK

3. 21-May-15 Physics 1 (Garcia) SJSU Density Define density as mass per volume, ( Density ) = Densities ( in grams per cubic centimeter ): Gold: 19.3Mercury: 13.6Lead: 11.3 Iron: 7.9Water: 1.0Cork: 0.2 ( Mass ) ( Volume ) (See Table 12.1, page 232) Liquids

4. 21-May-15 Physics 1 (Garcia) SJSU Demo: Gold Brick Compute density of gold brick. Dimensions: (20.5 cm)x(10 cm)x(5 cm) Volume: 1025 cubic centimeters (= 1.025 liters) Mass: 11,600 grams (about 26 pounds) Density = (11,600) / (1025) = 11.3 g/cm 3 Check with table that this is density of…

5. 21-May-15 Physics 1 (Garcia) SJSU Demo: Fool’s Gold Use displacement to find irregular volumes. Pyrite (called Fool’s Gold) is an iron ore (FeS 2 ). Pyrite sample has: Mass: 61 g Volume: 12 cm 3 Density =( 61 ) / ( 12 ) = 5.1 g/cm 3 About a quarter the density of real gold.

6. 21-May-15 Physics 1 (Garcia) SJSU Check Yourself Water expands when it freezes into ice. Which has more volume, kilogram of ice or kg of water? Which has more mass, a kg of ice or a kg of water? Which has a higher density, water or ice (or the same)? Which has more mass, a liter of ice or a liter of water?

7. 21-May-15 Physics 1 (Garcia) SJSU Density of Water One liter of water (1000 cm 3 ) has a mass of one kilogram (1000 grams) so density of water is 1.0 g/cm 3. Density of water varies slightly with temperature, becoming less dense as temperature rises. Warm water rises and cold water sinks. Density of ice = 0.92 g/cm 3 Density drops on freezing