Lay strip of paper on table so that
part of
it hangs over the edge. Invert flask and set it on the
paper.
Hold the free end of paper with one hand and hit it sharply at its
center
with the other. This should jerk the paper out from under the
flask
while leaving the flask undisturbed.
This demonstrates that there
is a
maximum
force of static friction between the flask and the paper. Pull
the
paper with a small force and the flask comes with it. Jerk it out
with a large enough force to exceed the frictional force and the paper
can be removed without moving the flask.
NOTES
Variations include:
pulling a dollar bill from between
two coke
bottles - the top one inverted over the bottom,
the embroidery hoop, chalk and coke bottle setup,
the card snap, for which we have
a commercial
apparatus,
the tablecloth pull - which
requires a seamless
tablecloth and practice,
the egg, pie pan and beaker trick.
