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.
Compressed Air
An interesting and effective experiment may be performed with compressed air. The arrangements are very simple and the requirements few.
Fig. 18.—Walnut shell with necessary holes bored.
Divide a walnut shell into two, and bore a hole in the bottom of each half. In one of the cups thus obtained make another hole half-way up the side, as in [Fig. 18]. Now, with a little sealing-wax fasten three straws into these holes.