Physics & Physical Science Demos, Labs, & Projects for High School Teachers

Pulling out the Tablecloth

Posted on: June 1, 2008


I hope everyone that teaches inertia does this demonstration. I let the kids do it also. I have a couple dos and don’ts for making this a success.

  • Pull the tablecloth out with a quick, single motion.  If you pull slowly, friction will start the dishes moving towards you.
  • Choke up on the tablecloth. You want to have your full arms length to pull it. If the cloth is slack, you might only pull the tablecloth half way out.
  • Friction is your enemy. A smooth, silky tablecloth works better than a rough, burlap bag.
  • Pull quickly and pull slightly down. If you pull upward, you are likely to launch the dishes into the air.
  • Make sure the tablecloth doesn’t have a hem. The edge of the plate and cup will snag on these and go flying.
  • I tried this the first time with a dollar store tablecloth. The plate didn’t move, but the cloth ripped in half. Just a heads up.
  • I’ve never had a failure at this demonstration.  The closest I’ve come is when one of the kids does the trick and starts to pull up.  I usually stand close by when it’s their turn.

I always tell the kids to make sure you go home and try this with mom’s good china. 😉

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What’s New in 2013/2014?

Every year brings a change, this one is no exception.

I will be picking up the sophomore honors Algebra II class to keep them separate from the juniors. This should help accelerate them and put them on a stronger track towards Calculus. Looks like there will be only one section each of Physics and Calculus, but still two of Robotics & Engineering.

Hot topics this year are going to be the Common-Core Standards, Standards-Based Grading (SBG), improving AP Calculus scores, and somehow adding Python, maybe as a club.

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