This two-part lesson plan focuses on the question, "How can you plan and conduct an experiment to explain how speeds change when objects collide?" It is the second lesson of a unit developed to explore this question. The lesson starts with videos of bowling as a "hook" to prompt learning about energy and speed. Students then have the opportunity to design their own investigations using common materials (cars, balls, meter sticks, blocks, ramps) to change one variable and collect evidence the speed of objects changes when they collide. To see the rest of the unit, including part 2 of the lesson, click on “Lesson 2” at the top of the lesson plan screen.