A Multipurpose Spectroscope

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 12 Issue 3 (2007) pp 152-154

A Multipurpose Spectroscope

M. Farooq Wahab

Department of Chemistry, University of Karachi, Karachi-75270, Pakistan, farooq.w@gmail.com
Received April 23, 2006. Accepted August 15, 2006.

Published online: 4 June 2007

Abstract. Construction of a simple multipurpose spectroscope using easily available objects is described. A cardboard box, a ball point pen, razor blades and a DVD are required. Commonly used CD/DVD spectroscopes suffer from the drawback of being coated with a plastic material which gives rise to multiple back-and-forth reflections and sometimes distorted images. Also, the diffracting material has to be inserted in the box at a specific angle in order to see the spectrum. This modified spectroscope employs surface grating from a DVD and a rotatable grating assembly to eliminate the problems experienced in such spectroscopes. A simple method to obtain a persistent yellow emission of sodium in a flame and obtaining its emission spectrum is explained. Observing the spectra of common light sources and the concept of self-absorption in a sodium street lamp are described to demonstrate a very important concept of atomic spectroscopy. The same assembly is also used to explain the idea of complementary colors and the exception to it using colored solutions and fluorescent ink from a yellow highlighter respectively.

Key Words: Laboratories and Demonstrations; analytical chemistry; demonstrations; introductory spectroscopy; teaching/ learning aids

(*) Corresponding author. (E-mail: farooq.w@gmail.com)

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