How Does It Work
The only way to make this work is to just do it. If you’re nervous, start with only a dinner plate and do it over a carpeted floor. You’ll be amazed when it works and you’ll add a saucer, then a cup, and so on. Be sure to thank Sir Isaac Newton for his help in making you an overnight success.
Plain and simple, the Tablecloth Trick works because of inertia. In his First Law of Motion (there are three), Newton described inertia as the tendency of an object at rest to remain at rest unless a force acts upon the object to move it. Inertia for an object in motion is the tendency for that object to remain in motion, unless a force acts on it to speed it up, slow it down, stop it, or change its direction. In terms of the Tablecloth Trick, inertia is the key. The inertia of the stuff on the table keeps them where they are despite the speeding tablecloth underneath them.
There is, however, another component to consider: friction. As explained, all of the objects (the plate, bowl, cup, utensils, etc.) are at rest. When you pull the cloth, friction between the cloth and the bottoms of the dishes acts on the them for a short time in the direction of the pull. Except, the tablecloth is “slippery,” so the force of friction is small and the cloth slides out from underneath the objects without dragging them too much. It helps to have a very smooth tabletop, as well. A towel or blanket would bring a lot of friction to the party and would be a poor choice as a tablecloth for this activity.
