The SpillNot is an ingenious gadget that will let you carry an open beverage without spilling it. With a little bit of practice, spin a cup of liquid around in a circle without even losing a drop! The forces in action will fascinate your students and challenge their analytical reasoning. The SpillNot employs simple physics in keeping your coffee cup from spills and breakage. By carrying the moving cup containing liquid, several forces act on the cup, and consequently on the liquid contained inside. If balanced forces are applied to a cup of liquid (..whether at rest or moving with a constant velocity), the liquid remains virtually undisturbed. However, once an unbalanced force is applied to the cup (ex. A force greater to the right than to the left), the cup will accelerate. The liquid's mass will not accelerate with the cup due to its fluid nature; instead, accelerating the liquid will cause the liquid to spill out of the cup; due to inertia and the liquid's inability to keep up with the accelerating cup.
