The morning news. [volume] (Savannah, Ga.) 1887-1900, 1899-02-26
A BIT OF SCIENCE MAGIC.
How "a BOiI Water by simply Hold
ing the Hands Around the Bottle.

How 10 boil Water by simply Hold
ing the Hands Around the Bottle.
New York, Feb. Pain the course of his
experiments the other day, Prof NJ l.
Pupin of Columbia College, New York, did
very remarkable thing. He made water
boil simply by holding his hands around
the outside of the bottle which contained
It, He also made the water boil by dash
ing or pouring water against the sides of
the bottle. 1t was a very curious trick,
and one well calculated to
excite wonder II the secret be
not known. Yet any boy may perform ID
in his own home with little trouble No
apparatus except a bottle is needed. The
bottle, however, should be one with long,
thin ncck. Prof. Pupin used one which
looked like those used 10 decorate the
shelves of French or Italian restaurants.
Such bottles generally are wound with
straw 10 prevent breakage, and a restau-
rant keeper win sell you one for few
pennies.
Fill your bottle half full Of water and
place 1t over a gas Jet or a flame until
the water boils. When il bols fiercely re-
move the flame and at the same time
quickly place a cork In the mouth of the
bottle OF course the water will instantly
stop boiling when the flame is removed
but IL you now turn the bottle upside down
and pour water on the outside, the water
within will again boil fercely. IL at this
juncture you take the bottle without the
hame) into another room full of unsus-
peeting friends, and show them how to
boil water with water they will be very
much surprised But you will add 10 their
establishment II in a moment (when tho
bottle bottom has become cold enough) you
place both Of your hands around the out
side Of the bottle; for the water inside
will again boil iercely.
Any boy who owns a bicycle pump map
add to the fun of the occasion. He will
be able to do exactly the opposite of the
above That is, he win be able TO make
water stop boiling even when there Is a
flame burning brightly under II. To do
this, il Is necessary merely 10 pump air
into the bottle in which the water Is boil
ing. No matter how violently the water
may be boiling, 1t Will cease doing SO
the instant fresh air is pumped into the
bottle. You may attach the pump to the
mouth of the bottle by means OF short
length of rubber tubing.
Now, the reason for the above phenom-
ena Is very simple. It Is all a question of
how hard the atmosphere presses down on
the surface of the boiling water. A col
umn OF air many miles high presses down
on everything on the earth. When water
boils II must generate heat and power
enough TO overcome the pressing Of this
air on its surface. If you were
somehow to remove this pressing
air, water would boil much quicker and AZ
lower temperature than II does ordnar-
ily On the top Of a very high mountain
or in vacuum, water will boil at low
temperature. Now, when IN the first in
stance you took the flame from under your
bottle and at the same time placed q
cork In the mouth, you thus prevented the
air from pressing on the water at mo-
ment when the bottle contained nothing
but water ana steam. When you turned
the bottle upside down you effectively pre-
vented any more air from getting inside
There was, of course, small empty space
between the surface Of the water and the
bottom (now the top of the bottle There
was vacuum there. You win remember
that the water must yet have been quite
hot after you removed the flame 1t was,
in fact, nearly at the boiling point in or
binary air, yet you suddenly removed that
air pressure and placed the fluid In
vacuum. II would now boil at a much
lower temperature than before and being
already quite hot, the heat of your hands
around the warm bottle was quite SUM-
cient to set Il off.