What is a simple experiment on projectile motion.?
First, you should review some equations that describe projectile motions, then prepare a toy gun and try to shoot something. You can assume that the gun will shoot the bullet at the same initial velocity every time(this is a good assumption). The easiest way to find this unique initial velocity is to shoot the bullet vertically, measure the distance it travels or the time(either of them is fine), and then you can use the kinematics equations to solve for the initial velocity of the bullet (with the acceleration 9.8m/s^2). Measure the velocity several times and take the average result. Now you have the data of the initial velocity and the angle of elevation(you’re free to choose!), Plug them into the set of equations I told you to review and with that, you can easily use conduct this experiment and calculate many interesting quantities: distance, time, velocity, height, best angle,…..