stupid human tricks

[Brett Dikeman]

At 2:45 PM -0400 7/7/03, <auditude at cox.net> wrote:
>I remember as a kid taking a lemon from the backyard tree and
>putting it into a steel can filled with gasoline.  The idea was to
>light the gas and shoot the lemon out.  Incredibly (for me at the
>time) I couldn't get the gas lit.  I was probably lucky in that case.

A couple of years ago, a friend and I endeavored to make a pneumatic
potato cannon.  It was quite the contraption, featuring several feet
of 3" PVC for a temporary air tank(I later learned from reading about
compressor piping how prone PVC is to shattering, makes me flinch a
little now), and we used a water sprinkler valve actuated by a small
electronic circuit w/two buttons- safety first! :-)  The sprinkler
valve provided some fantastic flow rates, especially with the nearly
1" pipe on in the inlet.

Our first tests were indoors in his basement, where we set up an old
blanket to "catch" the projectile- a permanent marker that was
precisely the right "caliber".

We blasted the marker right through the blanket with only 30-40 psi.
So much for those physics demonstrations with the blanket stopping
the fastball.

After careful evaluation of the first dataset, we elected to move the
testing facility outdoors to his back yard, and managed to launch a
broom handle about 300 feet.  Time for potatoes.

Around that time his parents came home, and the reactions were priceless.

His mother: "Are you INSANE?"
His father: "Oh cool!"

Our demonstration of its french-fry making capabilities(hint: tennis
racquet) was well received but deemed too messy.

That, however, was nothing compared to the egg catapult we
constructed in high school for Science Olympiad, which was capable of
launching an egg at least a football field's worth- featured a geared
time-release mechanism, vise-grips trigger, and a composite
arm(aluminum shower curtain rod with balsa wood core).  It was also
probably the least sturdy thing I ever built(the carriage bolts
stripped their wood holes under load- we ended up stuffing the holes
with notebook paper to keep the frame together), and quite capable of
probably killing someone.  Its components disappeared pretty quickly
from the garage after the competition, and MA's state law on
"infernal devices" rendered further experimentation and refinement to
be of questionable legality.


>One thing I did think was cool for a while was taking corn starch
>baby powder and lighting clouds of that.

Nah, what's better is gently sifting some into a tube, over a lit
candle.  Sift a little quickly, take several respectful steps back.
Fine flour works best, I'm told.

B
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