1. Aim: What is Density? Do Now: 1)In your notebooks, describe how to find the density of an object (formula) and explain why cutting an object doesn’t change density.

2. I. Density: The amount of matter in a specific volume - A physical property of matter. - Measured in g/cm 3 (grams per cm3) - Used to help identify matter.  D = M V

3. Using the one density formula you can rearrange the variables to solve for and factor. Density Mass Volume =Density Mass =Density xVolume Mass Volume = Density

4. D M V

5. II. Buoyancy vs. Density Buoyancy is the tendency of an object to float in a liquid. - determines if an object will sink or float **Less dense materials float on more dense materials.

6. ** Density of an object remains the same no matter how many pieces it’s broken in to ** Ex. The density of 20.0g of aluminum = 2.7 g/cm3 The density of 99.0g of aluminum = 2.7 g/cm3

7. Example: Compare the density of H 2 O (water) to the density of an ice cube. THINK An ice cube floats in H 2 O because it has a density: a) Equal to the density of water b) Greater than the density of water c) Less than the density of water d) None of the above

8. THINK Why does a steel ship float in water? Densities in grams / cm3 D (water) = 1.0 g / cm3 D (wood) = 0.8 g / cm3 D (steel) = 7.8 g / cm3 D (lead) 11.3 g / cm3 D (air).0012 g / cm3

9. Answer: A ship has a steel shell that is hollow inside. The volume is mostly air. The ship and air together have a density less than water.

10. Closure: From the side table take a density review worksheet from the top bin to work on in class with your partner.