Materials needed:
Cardboard
box (12 by 12 by 12 inches works fine, but the dimensions aren’t
critical);
Plastic
sheet, such as heavy-duty trash bag material;
Packaging
tape;
Hydrochloric (Muriatic) acid, HCl;
Household
ammonia, NH3OH solution;
Paper
towels;
Gloves.
Tools Needed:
Box
cutter;
Marking
pen;
Tape
dispenser;
Circle
template (pie plate, etc.).
Construction of the cannon is simple:
Cut
the four flaps from one end of the box.
Fold
the flaps on the opposite end closed.
Mark
these flaps with a circle whose diameter is about half the length of the
side of the box (6 inch hole for the box in our example. Cut out the
circle in both layers of flap.
Tape
the flaps closed. Reinforce the circle edge with more tape.
Cut
a sheet of plastic to fit the open box end with about 5 inches of excess
on each side.
Tape
the plastic sheet over the open end of the box. Allow plenty of sag in the
sheet. Seal the sheet to the box on all sides.
Construction
of the air cannon is complete.
Operating the air cannon:
Pinch
the sheet in the center and pull out.
Aim the air cannon.
Slam the plastic sheet with your palm to send a blast of air toward your
target.
Giant Smoke Rings
The air cannon will produce smoke rings if
you fill the box with smoke before you fire. The type of smoke I use is
produced by combining the vapors of hydrochloric acid and ammonia. This
“smoke” is ammonium chloride and water mist.
To do this, pour a little bit of each liquid
onto separate paper towels (while wearing gloves), and drop both towels into
the air cannon. But watch out! Both vapors are very noxious before they
combine. The acid fumes can cause damage to lungs and eyes. Keep your face away
from the opening of the cannon, and don’t fire it towards the faces of others.
Alternate Fog
You can avoid the hazards of working with
acid by generating water fog using dry ice. To do this conveniently, construct
a fog generator,
and attach the hose from it to the Giant Air Cannon.
The Saturday scientists