self-contained
Description:
Place
marble
in
well
at
the
end
of
the
board
and
elevate
the
board
such
that
the
marble
is
lined
up
with
the
vertical
bar.
Drop
the
board,
and
the
marble
will
appear
to
have
jumped
forward
along
the
board
in
its
descent,
landing
in
the
plastic
cup
with
silicone
in
the
bottom.
Take
time
to
play
with
this
demonstration
beforehand,
as
the
method
of
dropping
the
board
requires
practice.