| In NO SOUND THROUGH EMPTY
SPACE, a jar containing a bell, a fan and a pinwheel lets visitors
investigate what happens to sound in a vacuum. When the jar is filled
with air, the bell rings and the spinning fan causes the pinwheel
to turn around. When the vacuum button is pushed, evacuating the
jar, the pinwheel stops spinning (even though the fan is still turning)
and the bell's ring becomes difficult to hear (even though the striker
can still be seen hitting the bell).