The classic "whip off" the tablecloth trick is a must for any aspiring science demonstrator who wants to be amazing! This experiment is guaranteed to either bring down the house or to get you into a lot of hot water. The idea is really quite simple - yank the tablecloth out from under a beautiful place setting without destroying the meal (or the place setting). It’s easy if you take a science lesson from Sir Isaac Newton.
- Flat tabletop, preferably with a straight edge
- Dinner plates, saucers, and glasses with smooth bottom surfaces (the heavier, the better)
- Spread the tablecloth out onto the tabletop with about 2 feet of the tablecloth on the table. Make sure there are no wrinkles.
- Place the cups, plates and utensils on top of the tablecloth close to the edge of the cloth (for starters). This makes for less tablecloth to have to pull out from underneath the stuff on top.
- The trick is to grab the ends of the tablecloth with both hands and quickly pull the cloth straight down and away from the table. The key is the quick, downward motion - almost like you're whipping or yanking the cloth away. Keep saying to yourself, “Pull down… not out.” Make sure to pull perpendicular to the table and not at an inclined angle.
- 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. Okay, stop reading and try it!
Experimentation with Mom's best dinnerware probably isn't a great idea. In this case, "taking it further" might get you into a world of trouble. Instead of testing out different plates, bowls, and glasses, try experimenting with different masses on the plates. Make the plate or bowl heavier by adding a piece of fruit or something with some weight. Is it easier or harder to whip off the tablecloth?
How Does It Work?
After you take your bows and graciously accept your standing ovation, 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. Newton first described inertia as the tendency for an object at rest to remain at rest until a force acts upon the object. Inertia for an object in motion is the tendency for that object to remain in motion, unless a force acts upon the object. In terms of the Tablecloth Trick, inertia is important because, according to the law, the objects (the stuff on the table) will not move unless an outside force moves them. This is known as Newton's First Law of Motion.
There are two different parts of this experiment to discuss - inertia and friction. Initially, all of the objects (the plate, bowl, cup, utensils) are at rest (not moving). According to Newton's First Law, objects at rest tend to stay at rest. When you pull the cloth, friction acts on the objects in the direction of the pull for a short time. The tablecloth is slippery, so these forces are small and the cloth sneaks out from underneath the objects.
If you do it just right, everyone will be amazed. Next time your mom asks you to clear the table, do it with flair!
If you aren't sure about ripping the tablecloth out from under Mom's dishes, try placing a piece of paper under a heavy object on the table. The object should sit on one side of the paper and the rest of the paper should stick out over the edge of the table. Hold the edge of the paper in one hand, and with a quick downward motion (think karate chop!), use your other hand to "chop" the paper and pull it out from under the object.
- Mrs. Novello's 5th Grade Science Class Review by Mrs. Novello
This demonstrates Sir Isaac Newton's First Law of Motion. The First Law of Motion states that an object in motion will stay in motion and an object at rest will stay at rest unless acted upon by an unbalanced force or outside force. This shows the First Law of Motion because when he pulled the table cloth, the dishes stayed at rest. The table cloth moved because a force acted upon it. A force is a push or pull. In the case of the table cloth, it was a pull. Since the table cloth and dishes aren't connected, according to the First Law, the dishes started at rest and should stay at rest because they weren't impacted by a force. The table cloth, however, was impacted by a force and therefore was the only object that should move.
(Posted on March 13, 2012)
- Inertia is Incredible Review by Mrs. Rosser's Class
This response is from Mrs. Rosser's 5th grade class:
This shows Sir Isaac Newton's First Law of Inertia. An object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by an outside/external/unbalanced force. All of the objects are all at rest while on the table, but now the tablecloth is suddenly in motion. Since the items on the table are not attached to the tablcloth, this motion caused all of the items on the table to try to stay at rest. Thus, the items do not fall off the table when the tablecloth's potential energy is released and becomes kinectic energy.
(Posted on March 8, 2012)
- OMG!! Review by Christine Nguyen
Man.. i wonder if the more objects we put, the harder it is to pull. but this was a kool experiment that does deserve 5 stars!! YES-SIREE!!
(Posted on July 11, 2011)
- Awesome Surprise! Review by Diane Slack
I tried this with my first graders. At first they were very hesitant & skeptical. But once they got the hang of it (only 2 or 3 tries), they were instantly hooked! Now they want to show their family, friends, & other teachers!
(Posted on November 19, 2009)
- Amazing!! Review by Daniel Mak
I was supposed to do an example for Newton's 1st law of motion, that a motion at rest will stay at rest until an unbalanced force acts upon it. I showed this to my classmates, slowly setting the desk and telling them how they probably might've seen this in magic shows or performences. They finally get what i was going to do, and as I yank the tablecloth, the dish and silverware stayed, and the glass of water remained unspilled. Everyone was stunned, even the teacher. I highly recommend this trick when teaching or performing the physics unit.
(Posted on January 11, 2012)