This TWO-PERIOD (or 90-minute) activity is designed to come BEFORE learning about slope. It will allow students to discover through experiments what slope means and how to find it. Students will drop tennis balls, baseballs, and "SuperBalls" and measure their bounce heights from various distances. My entire department uses this as part of our International Baccalaureate program for the unit on graphing linear equations. After this activity, your students should better understand slope, which should require you to spend less time with drill-and-practice afterward.
Before you are frightened-off by this activity, please know that this has been used in every Algebra 1 classroom in an urban high school for the past two years without disaster. You can do this! I have included some tips to help you prevent mayhem.