TORNADO WARNING :  A tornado has been spotted!  Take cover
immediately!  A tornado is the most violent of all storms, with winds
that may exceed 300 miles per hour.  Conditions must be right for
the formation of this deadly storm.  Tornados develop when a
layer of warm, moist air blankets the ground while a layer of
cooler air hovers above.  As the warm air rises, it begins
to cool.  Air currents make the column of rising air begins
to rotate, forming a funnel.  In our experiment, the warm,
moist air is provided by boiling water on a hot plate and
heat from the lights.  The warm air begins to rise
through the stovepipe, carrying the steam with
it, while cooler air from the outside enters the
box through the gaps on eachside.  Since there
is one slit in each corner, the air tend to flow
 in a spiral inside the box.  Meanwhile, the
fan draws the air upward, increasing the
suction.  To run, take off the masonite,
fill the pie pan with water, and
replace the masonite.  Turn
on the hot plate and lights.
Run for cover!
It's a twister!

Try the Tornado!

                                                        1.  Plug in the lights, hot plate, and fan.  When steam
                                                                appears, turn ont he fan to produce a twister!

                                                        2. Try changing the fan speed to high.  Does the

tornado behave differently?  Now turn off the fan.  
What happens?

                                                        3.  Slide the glass panels to different positions.  Does

this affect the tornado?