*NOTICE that as the projectile goes from left to right across the page, that the gaps between the dots STAY THE SAME DISTANCE APART.

*NOTICE that as the projectile goes up and down, that the gaps between the dots ARE MORE SPREAD OUT NEAREST THE GROUND AND CLOSER TOGETHER NEAR THE TOP OF THE FLIGHT PATH.

SITE 1: you can mess with all the variables like angle and velocity.  (I suggest you keep the dot-trail option "on" so you can more easily notice the above points)

SITE 2: a little less educational, but cooler because you get to shoot at a target