Lead or metal brick, hammer, Liq. N2, small dewar, tongs, pennies
Shattered 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 Chemistry and Physics of Everyday Experience

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.