BUILD AN ANTIGRAVITY BOULDER
Bill Beaty 2003
Tie a piece of carrot to a mylar helium ba lloon. The weight of the
carrot will drag it down. Nibble the carrot smaller. If you do it
carefully, you can find the weight that cancels out the bouyancy. It
will neither rise nor sink. Instead it will drift annoyingly
around the room.
Years ago there was a helium tank at work, and I had a mylar
"emergency blanket" in my car. I have an idea: giant floppy
balloon! So I duct-taped the mylar into a roughly tetrahedral
bag-shape about
80cm across and filled it with gas. It gave considerable lift, and it
needed a
considerable counterweight in order to attain neutral bouyancy. I tied a
plastic cup full of water to the bag and adjusted the amount of
water.
Brainstorm!
Cover the whole thing with duct tape so the
counterweight is
distributed completely evenly. There would be no single weight at the
bottom. That way it would behave like a boulder in
free fall: it would remain in whatever orientation I put it in (rather
than rotating to put the weight at the bottom.) And when gently spun (or
after any
collision) it should continue rotating around any axis for a long time.
So I started applying 20cm strips of black duct tape to the mylar bag,
letting it stablize before applying the next strip to the (new)
top location. That way it tells me how to distribute the
duct-tape-mass evenly (I always put the next piece of tape directly
across from the heaviest spot.) Then I applied smaller and smaller
strips
as I got closer to zero lift.
It worked great. I ended up with a
huge, black, misshapen "boulder" which drifted around the room.
If bumped, it would rotate end over end like an asteroid. I
could grab it and fling it at somebody, and it would strike them
with considerable impact (since it probably massed about half a kilogram
not including the surrounding air mass it would entrain.) When thrown, it
looked very unnatural, since we'd expect an object to fly in a
parabolic trajectory. This one was completely straight.
It also seemed very strange to encounter a large thing drifting around
in the warehouse. After about half a day it settled to the floor
as a bit of helium slowly escaped and increased the downwards net force
so much that air convection could no longer waft it around the space.
But I could then remove one or two tape strips from the
bottom to restore it to "zero weight" again.
Next time: use white tape instead of black, then use an airbrush or spray
paint
to sketch in lots of lunar craters. Or perhaps print out some
actual asteroid photos on 11x17 paper and plaster them all over the
surface with #33 spray-on rubber cement (then add some extra helium to
compensate.)
Someday I also want to make about fifty of these things and leave
them in a big lab at work early in the morning before the victims
arrive.
Anyone remember the Rocky & Bullwinkle episode about the old
prospector and his mine where he was digging out negative-mass
mineral called "upsi-daisium?"
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