This lesson introduces students to the concept of momentum. A Zorb Soccer video is used to engage the students, and make them think about mass and velocity as properties that give a player an advantage. This is followed by a Car Crash Lab, where students explore different scenarios of elastic and inelastic collisions, and explosions using cars on a tracks. Students explore simulations involving collisions, and make measurements of mass and velocity before and after collision. Students begin to appreciate that the product of mass and velocity is a quantity that is conserved in the collisions, thus leading into the definition of momentum. Students submit answers to a few questions online, to provide formative assessment of the concepts learnt in the class.
Students practice conservation of momentum problems, through activities modeled as games: "Find the mistake" and "Grudgedart". In the "Find the mistake" game, the students work in groups to solve a problem on whiteboard, making at least one intentional mistake. The other groups that review the problems of their peers, and try to spot the mistake. This has the students thinking about common mistakes made in momentum problems, and also approach mistakes as a means to learn from. In the "Grudgedart" game, students answer problems in groups again, and get an to shoot darts with a nerf gun for correct questions. The points earned can be added to their team score, or taken off from another team's score. As teams try to get even with each other, they are solving momentum problems in the process.
This lesson introduces the students to the concept of impulse. Students design a barrier to reduce the impact of a car crash, measured using an acceleration sensor, and observe the change in peak force of impact with and without the barrier. Students observe that the product of force and time is a constant in the two scenarios, leading to the definition of impulse. Students also observe that the loss in momentum in the car is the same as the impulse delivered by the wall or barrier.
Students then go outside and throw an egg into a sheet of cloth, observing that it does not break. Then they throw an egg on the wall and see it break. They explain the difference in terms of peak force on the egg, and how the impulse delivered to the egg is spread out over time, relating back to the barrier. Then students come back into the class, and watch a demonstration, where a bouncy ball and an inelastic ball are each rolled down a ramp, and try to knock down a book standing vertically. They need to predict which one can knock down a book standing vertically, and challenges the misconception that an inelastic ball that comes to a stop has more change in momentum than a bouncy ball that reverses direction. Students submit answers to a few questions online, to provide formative assessment of the concepts learnt in the class.
Students practice Impulse problems in groups, modeled as a "Grudgedart" game (see lesson #2). Students then take an individual written quiz, as practice for the district test, as well as to provide feedback to them on areas in which they more preparation.