E-Book Content
Martin Gardner's
Science Tricks
ustrated 18 x
by}
Tom Jorgenson
Boston Public Library
Martin Gardner's
Science Tricks
by
Illustrated
Tom Jorgenson Rositndole Brands i?5 -— rv 4238 Wasfcinrto, Rosfmdofa, MA 02 1 3 -25 7 i
i
1 Sterling Publishing Co., Inc. New York
RO BR J
Q164 .G25 1998x
10
987654321
paperback edition published in 1998 by Company, Inc. 387 Park Avenue South, New York, N.Y. 10016 Originally published in hardcover as Science Magic © 1997 by Martin Gardner Distributed in Canada by Sterling Publishing % Canadian Manda Group, One Atlantic Avenue, Suite 105 First
Sterling Publishing
Toronto, Ontario,
Canada
M6K 3E7
Distributed in Australia by Capricorn Link (Australia) Pty Ltd. P.O.
Box
6651,
Manufactured
Baulkham in the
:
I
Hills,
Business Centre,
niteshigahara tend he
is
of Tokyo,
who
invented this stunt, likes to pre-
putting a drop of invisible glue on the middle of each card
before he does the pickups.
Air pressure keeps the cards together. cloth surface or
The trick works only on a hard rug, otherwise the cards stick to the surface. 18
Three Bernoulli's
for Bernoulli
principle states that air in rapid motion will lower the
air pressure along its path.
Here are three easy ways
to
demon-
strate this. 1.
Hold a drinking glass in one hand and with the other hand
hold a burning match behind
goes out as 2.
if
it.
Blow toward the
you blew right through the
glass.
The flame
glass.
Cut two long narrow strips from a newspaper. Bend your
head forward and hold the ends of the strips on either side mouth. Blow
down between
come together instead 3.
of
your
the strips. You will see their lower ends
moving
apart.
Push a thumbtack or pin through the center
card. Holding the card horizontally, place tack.
of
As you blow down through the hole,
let
19
a business
go of the card. You would
expect the card to be blown off the spool, but instead spool's underside.
of
a spool on the card over the
it
clings to the
A Blow for Bernoulli There are many well-known ways to demonstrate the Bernoulli effect,
but here's a simple demonstration that
is
not so well
known. At one end of a ruler, fasten a paper strip with a slight hump center as shown.
The
strip's
in the
ends can be pasted down or held with
rubber bands. Place the ruler crosswise on a round-stemmed pencil. Roll the pencil
back and forth
until the
end of the ruler with the paper
strip very slightly overbalances the ruler's other end.
Blow toward the ruler. Air rushing over the strip's bulge will lower air pressure
above the bulge and cause the ruler to
tip the
other way.
: : ::::>::>>>>>>>>>>
The Mysterious Balloon
Can a toy balloon mouth stays l*ut
Ih>
inflated
open.' Hereto
and remain
how
to
do
this
way even though
its
it.
a few inches of water in a large glass bottle that has a small
opening. Sot the bottle on a low stove
remove the
bottle
light.
When
the water boils