TCE
    
|
The Chemical Educator
ISSN: 1430-4171 (electronic version)
Abstract Volume 17
(2012) pp 149-151
DOI 10.1007/s00897122432
Bottoms Up to the Scientific Method
Marc Hill and Eugene T. Smith*
Harriet L. Wilkes Honors College, Florida Atlantic
University, Jupiter, FL 33458 esmith@fau.edu
Received April 27, 2012.
Accepted July 14, 2012.
Published: 10 August 2012
Abstract. A laser refractometry experiment, which is appropriate for a general chemistry course, is described for use on the first day of class to introduce the scientific method. A common laser pointer is used to analyze the composition of ethanol/water solutions contained in a martini glass. A hypothesis, a tentative but clear and compelling explanation, is presented by the instructor regarding refraction of light. Students observe that alcohol content in water influences the position of a laser beam after being projected through a glass onto a white board. Students are asked to propose a law based on the observed differences in refraction of light by pure water and pure ethanol, and then the instructor tests this law using a cocktail. The inaccurate prediction of their law leads to a critical analysis of the problem and suggestions for additional experiments, which is followed up with a discussion on theory.
Key Words: Laboratories and Demonstrations; general chemistry; laser
(*) Corresponding author. (E-mail: esmith@fau.edu)
Article in PDF format (114 KB) HTML format
© The Chemical Educator 1996-2015