Storm glass

Crystals forming in a storm glass prior to a storm

A storm glass is a type of weather forecasting device, composed of a sealed glass container filled with liquid. The appearance of the liquid purportedly predicts the weather, but most modern experiments have failed to confirm this.

Description

The liquid within the glass is a mixture of several ingredients, most commonly distilled water, ethanol, potassium nitrate, ammonium chloride, and camphor. This specific mixture was developed by Admiral Robert FitzRoy and used on his voyage with Charles Darwin on HMS Beagle.[1]

During the historic voyage, FitzRoy carefully documented how the storm glass would predict the weather:[2]

In 1859, violent storms struck the British Isles. In response, the British Crown distributed storm glasses, then known as "FitzRoy's storm barometers," to many small fishing communities around the British Isles that were to be consulted by ships at port before setting sail.

Crystals in FitzRoy Stormglass

Ingredients

The potassium nitrate and ammonium chloride are dissolved in warm water and the ethanol and camphor are then added. The resulting solution is placed in a glass container and sealed.

Accuracy

An article in the Journal of Crystal Growth concluded that temperature change is the sole cause of crystal growth in storm glasses.[3]

Cecil Adams performed informal experiments with a storm glass and found that the success of prediction was no better than random chance.[4]

See also

References

  1. Storm Glass, Mount Washington Observatory
  2. FitzRoy's Storm Glass, About.com
  3. Tanaka, Yasuko; Hagano, Koichi; Kuno, Tomoyasu; Nagashima, Kazushige (1 May 2008) [1 February 2008]. "Pattern formation of crystals in storm glass". Journal of Crystal Growth 310 (10): 2668–2672. doi:10.1016/j.jcrysgro.2008.01.037.
  4. "Can storm glasses predict the weather?". The Straight Dope. October 15, 2010.

External links

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