Lead or metal brick, hammer, Liq. N2, small dewar, tongs, pennies

Code Number: 4A40.31

Demo Title: Liquid Nitrogen - Whack A Penny

Condition: Excellent

Principle: Material Properties at Low Temperatures

Area of Study: Chemistry and Physics

Equipment:

Lead or metal brick, hammer, Liq. N2, small dewar, tongs, pennies ( dates of 1999 or later ), Safety Glasses.

Procedure:

See also: 4A40.31 in Thermodynamics

Cool the pennies in the liquid nitrogen using the tongs. Put on the safety glasses, place the penny on the lead brick, and give it a good whack. The penny should shatter into several pieces due to the physical changes to the Zinc's crystal structure when cooled with the liquid nitrogen. Note: Newer pennies are used because they are mostly Zinc with a thin coating of Copper.

References:

William McNairy, "Baffling Buoyancy", 2008 AAPT/PIRA Apparatus Competition, An Entry for the Low Cost Category.

Disclaimer

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Instructional Resources and Lecture Demonstrations

4A40.31 - Liquid Nitrogen - Whack A Penny

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