The Vermont watchman. [volume] (Montpelier, Vt.) 1883-1911, 1892-03-16
Our Sons ano Girls.
Something About Air.

How many of the boys and girls who
like to throw open their windows in the
morning and breathe in deep breaths of
the fresh morning air can tell me any,
thing about this air that we breathe and
that we could not live without? Do you
know what it is made of? Do you know
of anything that it can do? / am going
to tell you of few little things that we
can do to find out something about it.
There is air everywhere. When we
say that anything is empty, we mean
that there is nothing in it but air. Let
us see how we can prove that there is
air in what we call an empty bottle.
Take wide-mouthed bottle like mus
tard bottle and make two small holes in
the cork. { rubber stopple is better
than cork.) Through one of the holes
put piece of glass tubing five or six
inches long, and through the other
very short piece of glass tubing, to
which is attached a rubber tube about
fifteen inches long. The tubing can be
bought at any drug store. Put the
other end of the rubber tube into a
second bottle nearly filed with water.
Now pour some water into the first bot
tie through the glass tube Ga funnel
tube is most conveniently, and bubbles
of air will rise through the water in the
second bottle from the rubber tube.
This air was in the first bottle, and had
to make its way out when the water
came in to take its place.
Now let us find out what air is made
of. Fill shallow plate with water.
Place very little piece of phosphorus,
with some powdered chalk, on fiat
cork which will float on the water. Set
fire to the phosphorus, and place over
it glass fruit jar-which is, of course,
full of air-letting the jar rest on the
bottom of the plate. AS the phosphorus
burns, the water will be seen to rise in
the jar until it is about one-fifth filled
with water. The phosphorus, in burn
ing, has taken something out of the air,
aud the water has risen to take its
place. Now lift the jar and hold
lighted candle up in it, and the flame
will go out. This part of the air that is
left will not let anything burn in it. 1t
is called nitrogen. The part of the air
that will let things burn in it is called
oxygen. These are two hard names,
but they are worth remembering, as
they are the names of two very impor-
tant gases which we may learn more
about some day.
One of the most important things
that air can do is to exert pressure in
different directions. We shall see how
it can press upward. Fill a tumbler
with water. Place a piece of bristol
board over the top of the tumbler.
Hold it there while you turn the tum-
bier of water over. Your hand is hold
ing the cardboard up; but take your
hand away, and the cardboard still re.
mains on the tumbler. What is hold
ing it there now? 1t must be the air.
The water is pushing the cardboard
down, but the air is pressing it up
harder than the water is pushing it
down, so it stays in place. Fill very
small phial with water and turn it over,
and the air will hold the water up.
This is another way to show that the
air presses downward. Fill a mustard
bottle nearly full of water. Fill very
small phal so that it will Just float.
Invert it in the bottle of water. 1t will
float inverted. Now stretch a piece of
thin sheet rubber, such as dentists use,
over the mouth of the mustard bottle,
and tie it down securely. Press on the
rubber with the finger. This will press
upon the water, which will so be forced
up into the little phial. The phial will
then be so heavy that it will sink to
the bottom of the bottle Christian
Union.