1. Lesson 4.2: Modeling Density
Density is the amount of matter an object has in a given unit of volume. You can calculate density by dividing its mass by its volume.

2. Comparing the Density of Similar Materials
Given the following information about two types of wood, which wood is more dense?

3. Density with respect to area instead of volume
Density can also be found with respect to area. The number of objects within a given region determines how densely packed a region is with that specific object. Population density is a good example of density with respect to area.

4. Population Density
Check out Example 1 on pg. 216 in your text. Burlington, Vermont has an area of 160 km2 and a population of about 109,000 people. What is the population density of Burlington? Now complete part B and Reflect 2 – 4.

5. Your Turn
Do Your Turn #5 on pg. 217 in your text.

6. Calculating Measures of Energy
A British Thermal Unit (BTU) is the amount of energy necessary to raise 1 pound of water one degree fahrenheit. One cubic foot of natural gas provides about 1,027 BTUs. How many BTUs are in a spherical container of radius 6 feet?