Remember that time on that field trip when the bus went out of control and skidded off the road and crashed through the guardrail and the front end was dangling over a precipice? Remember how, thinking quickly, you had everyone—the incompetent driver included—scamper the back of the bus so it wouldn’t tip forward into the abyss? While that was a very good demonstration of how weight distribution affects force and the movement of objects, it’s not one that you should attempt to recreate with this year’s batch of students. #ripkevin
Instead, try this handy dandy Demo Science science demo. The worst that’ll happen here is one student maybe getting dropped on his tuckus. He’ll survive. Probably.
Chairman of the Horde
The materials for this demonstration are all things you should have in your classroom already. You’ll need a more or less straight chair and six student volunteers. It doesn’t have to be all right angles and flat planks, just as long as it’s not like a beanbag chair or a Barcalounger. If your class somehow has fewer than six students, well, welcome to the final days of Carpio Elementary School.
Choose the volunteer who least dislikes getting poked and picked up by his or her fellow students to be the liftee; should also be non- or not-very-ticklish. All other volunteers will be lifters, whether they like it or not.
Have your liftee sit in the chair, as straight and rigid as possible. Have him clasp his hands in his lap, lean his head forward, and keep his neck stiff. Your liftee must be the anti-Gumby: unbending.
The other five volunteers should now take turns slapping the liftee each extend the index and middle fingers of their dominant hand, and steady that hand from beneath with the other, palm up.
Station one lifter at each knee of the liftee, two more behind the chair, and the fifth to one side or t’other, beside the seated student’s head. Your knee lifters should place their extended fingers under the liftee’s knees; those behind the chair should place their extended fingers under the liftee’s armpits; the final lifter should place his or her fingers under the liftee’s chin.
Make sure everyone is good and ready. Have all six snotty little punks involved take a deep breath, then have your lifters simultaneously lift straight upward on the count of “three”—make sure everyone is clear as to whether you’re going with “one, two, three, lift” or “one, two, lift on three”. Lifters must lift straight up, and steadily—none of that herky-jerky mumbo-jumbo beeswax banana sandwiches.
If they do it right—which, with grade schoolers involved, is about a 50-50 proposition at best—the seated student should be hoisted into the air as if he or she were light as a feather (provided the liftee remains stiff as a board). Tell your lifters to be very careful not to drop the liftee. That would be bad. (But not that bad—how far’s the kid gonna fall, like six inches?)
Science or Steroids?
So, how did the lifters lift the liftee? Doesn’t seem like two fingers each is the best way to lift someone into the air. Are they all on steroids? NO! Because there were five of them, and because the seated student did such a bang-up job of remaining rigid the whole entire time, each lifter was only carrying one-fifth of the liftee’s weight. Almost anyone can lift forty pounds! (Grade school kids usually tip the scales at like 200 pounds, right?)