Bologna bottle

A Bologna bottle, also known as a Bologna phial or philosophical vial,[1] is a glass bottle which has great external strength, often used in physics demonstrations and magic tricks. The exterior is generally strong enough that one could pound a nail into a block of wood using the bottle as a hammer; however, even a small scratch on the interior would cause it to crumble.[2]

It is created by heating a glass bottle and then slowly cooling the outside whilst rapidly cooling the inside. This causes external strength and internal stress such that even a scratch on the inside is sufficient to shatter the bottle.

The effect is utilized in several magic effects, including the "Devil's Flask."

Manufacture

To create the desired effect, the bottles are rapidly cooled on the inside and slow cooled on the outside during the glass-making process. This causes the stress to be concentrated on the inside of the flask, while the quick-cooled, compressed, extremely hard, and otherwise incredibly brittle glass on the outside is held together by those powerful internal stresses.[3] The glass is not annealed.[4][5] Reheating the glass and then allowing it to cool slowly will remove the unique properties from the glass.[6]

Uses

Because of the seemingly paradoxical nature of the glass (being both extremely durable and extremely fragile), Bologna bottles are often used as props in magic tricks.

See also

Bibliography

  1. ↑ Cooley, Arnold James (1854). A cyclopaedia of six thousand practical receipts, and collateral information in the arts manufactures, and trades including medicine, pharmacy, and domestic economy: Designed as a compendious book of reference for the manufacturer, tradesman, amateur, and heads of families. D. Appleton & Co. p. 124.
  2. ↑ Knight, Edward Henry (1876). Knight's American mechanical dictionary: A description of tools, instruments, machines, processes, and engineering; history of inventions; general technological vocabulary; and digest of mechanical appliances in science and the arts. Hurd and Houghton. p. 110.
  3. ↑ "Bologna Bottles Univ. of Illinois at Urbana-Champaign". UIUC Physics Lecture Demonstration Database. Univ. of Illinois at Urbana-Champaign. Retrieved 1996.
  4. ↑ The new American cyclopædia, ed. by G. Ripley and C.A. Dana. Beam-Browning. 1859. p. 450.
  5. ↑ "1913 Websters Dictionary via hyperdictionary.com". 1913 Websters Dictionary.
  6. ↑ The Locomotive, Volume 6. Hartford Steam Broiler Inspection and Insurance Co. 1885. p. 158.

External links