The Broken Bottle
An interesting and useful experiment with a broken bottle is depicted in [Fig. 15].
Fill the broken piece with oil to whatever level you desire it to be cut, and stand it upon a perfectly level table. Now plunge a red-hot poker into the oil and hold it there for a few seconds, when there will be a loud crack, and the top of the broken part will come off, even and smooth, as in [Fig. 16].
Fig. 15.—Portion of broken bottle for experiment.
Fig. 16.—Showing smooth break after red-hot poker has been plunged into the oil.
It may not be generally known that a sheet of glass may be cut regularly and evenly with a pair of strong scissors.
A glance at [Fig. 17] will give an idea of how this is done. The apparatus required is a large pail of cold water and a pair of strong scissors.
Plunge the glass, the scissors, and the hands, right into the water so that no part of either scissors or glass escapes immersion. You will now find that the scissors cut cleanly without the glass cracking or splintering.
The reason for this is that the water deadens the vibrations both of the scissors and the glass, thus insuring a neat and clean fracture.
Fig. 17.—A glass-cutting experiment.