FAMILY FUN

New Zealand Tablet, 20 February 1913, Page 62

FAMILY FUN

A Puzzling Illusion.—A very puzzling illusion may be presented in this manner. Procure a piece of thin board of soft wood, say pine. It would be a foot and a half in length and a couple of inches wide. Place it upon an ordinary kitchen table, allowing the end to protrude half its length almost beyond the edge of the table. Now place a newspaper upon the table, covering the board to the edge, and smooth it out carefully, being sure that the paper is in perfect contact with the board as well as with the table. Then announce to the company assembled that, with no other fastening upon the board than the sheet of newspaper, you propose to strike the end of the board hard enough to break it, or at least to tilt the table. It will appear impossible. Everyone will imagine that the newspaper will be torn in two as soon as the end offthe board is struck, but this will not occur. Strike it a smart, sharp blow with the hand or an instrument, and the board will either break off or - tilt the table and remain fast to it, just as if it had been nailed fast. The explanation is simple. When the blow is . struck there is n. tendency to tilt the end of tho board upon ~ •***' VWV OXXU WX LJUV UUCUJLU. UjJOX* the table, but the air having been pressed out from under the paper, a semi-vacuum has been created, and the compression of air upon the outer side of the paper holds the board fast.