TRY THIS Set a ball/marble rolling around the outer, upper edge on the curved surface. See how it rolls up and down between the 2 holes until finally falling into one. Can you repeat the motion? Can you predict into which well it eventually falls?
WHAT IS HAPPENING The ball loses/gains speed as it rolls up/down between the wells. It is converting between potential and kinetic energy along its path, while losing some energy to friction. The motion of the ball cannot be easily repeated as it depends on the initial starting roll. Try releasing along a line directly between the 2 wells. It is difficult to predict into which well it will fall! What if the ball is spinning as it starts? The ball simulates a planet revolving about a twin-star system. |
.jpg)
PS–30 
