The shrinking dollar bill

• Published in: Journal of chemical education Vol. 74; no. 11; p. 1357
• Main Author: Hermann, Christine K. F
• Format: Journal Article
• Language: English
• Published: Easton Division of Chemical Education 01.11.1997; American Chemical Society
• Subjects: Ammonia; Chemical Reactions; Chemistry; Currency; Demonstrations (Science); Density (Matter); Experiments; Higher Education; Liquid ammonia; Organic Chemistry; Science Instruction; Secondary Education; Demonstrations; Tested Demonstrations; High School / Introductory Chemistry; Consumer Chemistry
• ISSN: 0021-9584; 1938-1328
• DOI: 10.1021/ed074p1357.2

Everyone knows that the value of the dollar bill decreases each year, but there is actually a way of demonstrating a shrinking dollar. This demonstration can also be done with any other item made from paper, such as foreign currency, parking tickets, memos from your boss, or writing paper.Caution: The entire demonstration must be done in a hood. Wear goggles, protective gloves, and protective clothing. In the hood, fill a large Dewar flask or beaker halfway with liquid ammonia from an ammonia tank. (Ammonium hydroxide solution does not work.) Soak a dollar bill in the ammonia for a few seconds; then, using tongs, remove the dollar bill and allow the ammonia to evaporate from it in the hood. As the ammonia evaporates, the dollar bill shrinks. This process can be repeated several times to shrink the bill even more. To obtain an unwrinkled dollar bill, place the wet bill between two metal blocks and heat the blocks with a heat gun until the bill dries.We weighed the dollar bill before and after the process and found no change in mass. The smallest bill obtained measured of 9.8 cm by 4.8 cm. A normal dollar bill has dimensions of 15.7 cm by 6.6 cm.The chemistry of this demonstration is unknown at this time. Suggested explanations will be welcome.