I've got to explain how spin art works to some 5th graders tomorrow. Basic setup: Paper is attached to center of a horizontal disk. Paint droplets are placed at different places on the paper. Disk is spun which causes paint to produce a pattern flowing away from the center of the disk/paper. Basic explanation: As paper is spinning, a centripetal force is exerted on the paint (towards center of rotation) initially keeping it in place. As speed of rotating disk increases, the force required to keep the paint from wanting to follow a tangential path is more than the paper can exert on the paint, therefore paint droplet slides tangentially to the curved path of the paint. My thought is that the droplet moves in a straight path, but that it's actually not directly away from the center of rotation, but actually at an angle. Is that correct? It LOOKS like it's directly away from the center, but it doesn't seem like that's actually true... Thoughts?