This is a really neat lab and from past experiences it is one of the students favorites. The students are shown a projectile launcher (a ballistic pendulum with the pendulum removed), and how it works. They are also shown a photogate timer and then they figure out how it can measure the velocity of the ball that is to be launched. The projectile is then launched so that the students can see how the launcher works.. The students are told that their task is to figure out where on the floor the projectile will land for their gun which is placed level on a table top. The students have to figure out on their own where the ball will land and place a sheet of paper approximately 8 1/2 by 20 inches on the floor where they calculate that the ball will hit. They get one shot to hit the paper. However, they get as many shots as they want to measure the initial velocity of the ball which hits a plywood backboard so they can't see where the ball would land. If they hit the paper in their one shot they don't have to do a lab write-up, which is great motivation.