2. Everyone Ever Tell You are Dense? Well, you all are… Well, you all are… Because you all have these two properties You are made up of MATTER…which means you have mass You all have VOLUME…which means you take up space

3. When You Combine Mass and Volume, you get… Density Density A measure of the amount of matter that occupies a given amount of space SPACE Amount of Matter

12. Density Aim: How is density determined?

13. What is Density? Which one is more dense, a bowling ball or a soccer ball? Even though they are both approximately the same size and shape, the bowling ball is much more dense.

14. Density Therefore, density depends on the mass of particles and how closely packed they are. Density = Mass Volume

15. Let’s put it all together… DENSITY is the ratio of the mass of a substance to the volume of the substance UNITS: commonly expressed as grams per cubic centimeter for solids and liquids and grams per liter for gases

18. So now you’re going to say we need more units, right? Right!!!! Units for Density Units for Density = Grams per cubic centimeter g/cm 3

19. What Do All Those Letters Mean?

20. Quick Visual Aid

21. Want to See An Example Question? An unknown object has a mass of 15 grams and a volume of 5 cm 3. What is the density of this object? An unknown object has a mass of 15 grams and a volume of 5 cm 3. What is the density of this object? Density = Mass ÷ Volume Density = 15 grams ÷ 5 cm 3 Density = 3.0 g/cm3

22. Your Turn!!! An unknown liquid has a volume of 6 cm3 and a mass of 6 grams. What is the density of this liquid? An unknown liquid has a volume of 6 cm3 and a mass of 6 grams. What is the density of this liquid? Density = Mass ÷ Volume Density = 6 grams ÷ 6 cm 3 Density = 1.0 g/cm3

35. Find the Density of the Cube 10 cm 3 cm 8 cm Mass = 480 grams 480 g 240 cm 3 = 2 g/cm 3

36. Density Problems Calculate the density of a rock that has a mass of 40 grams and a volume of 5 cm 3. 40g/5 cm 3 = 8 g/cm 3 An unknown sample has a density of 8 g/cm 3. If the mass of the sample is 16 grams, what is its volume? 8 g/cm 3 = 16g/V = 2 cm 3 An unknown sample has a density of 10 g/cm 3 and a volume of 2 ml. What is the mass of the sample? 10 = M/2 ml = 20 g

37. Density Facts The Density of a substance remains the same regardless of size, shape, or mass of sample!!! Example: The density of a piece of aluminum is 2.7 g/cm 3. If you cut the Al bar in half, the density of each piece is still 2.7 g/cm 3 Even if you roll the aluminum into a sheet the density will still remain the same

38. Density of Aluminum D = 2.7 g/cm3 By simply cutting the bar in half, the density remains the same!!!

40. What will change the density of an object? Temperature As the temperature of a substance INCREASES the density DECREASES due to the expansion of the substance Inverse Relationship Most substances EXPAND when heated and CONTRACT when cooled

41. Warm air rises because it is LESS dense Cold air sinks because it is MORE dense

42. What will change the density of an object? PRESSURE As pressure on a substance INCREASES the density INCREASES DIRECT RELATIONSHIP

43. Material DENSER than water will SINK in water Material LESS DENSE than water will FLOAT Materials with a density EQUAL TO water may remain at ANY LEVEL When several objects of different densities float on water, the LEAST DENSE objects float HIGHEST.

44. A B C D Water: 1 g/ml Object D: 2 g/cc Object C: 1 g/cc Object B: 0.4g/cc Object A: 0.8g/cc Volume (cc) Mass (g) D C A B