Three Hundred Things a Bright Boy Can Do

by Unknown

If we take a cold clean tumbler and hold it over the flame of the candle (Fig. 1) we shall see that the inside becomes moist with water, and on touching it our fingers are made wet. On the tumbler becoming warm, this moisture disappears. If we could surround the tumbler with an ice jacket, we should see the water from the flame of the candle dripping down, and if this were caught in a vessel we could obtain from an ordinary candle about a wine-glassful of water. We may therefore produce water from a burning candle. The cause of the water being formed is that there is in the fat of the candle, as one of its constituents, hydrogen, and as the candle burns, this unites with the oxygen of the air to form water. Wherever water is found it always consists of hydrogen and oxygen in combination, and of nothing else.

Presence of Hydrogen Proved.—We may prove the presence of hydrogen gas by bringing a lighted taper within two or three inches of the wick of a candle just after it has been extinguished. On holding the lighted taper in the stream of smoke coming from the wick, we shall see a tiny flame run down the smoke and re-light the candle. The hydrogen gas coming from the hot fat is being carried off in the smoke. It is very inflammable, and the flame from the taper ignites it, and in turn rekindles the candle. When the stream of smoke has ceased, it does not matter how near we hold the taper to the wick without actually touching, it will not be re-lighted. (See Fig. 2.)

Fig. 2.

The Hydrogen Located.—A still better way of showing the presence of this gas is by bending a piece of glass tubing of small-bore, into the shape shown in Fig. 4.

Fig. 4.

Glass tubing may be bent easily to any shape by holding it in the flame of an ordinary gas burner. The tube becomes covered with soot, and this prevents its getting hot too rapidly, and so enables the tube to bend easily and evenly. The bending must never be forced, but very gently done as the glass softens. (See Fig. 3.) A little practice will enable any boy to make a first-rate bend.