TEACHING PHYSICS: Cost-effective experiments on the diffraction and interference of light

Experiments on the Fraunhofer diffraction and interference of light using computer-interfaced apparatus and data logging software are now available from suppliers of educational scientific equipment, and are a very useful tool for the teaching of these fundamental aspects of light. Clearly, however, cost imposes limits on the number of sets of apparatus which can be made available for student use. An alternative experimental arrangement is presented here, which results in a considerable cost saving by reducing the number of sensors and other apparatus required, while giving excellent quantitative results for comparison with theory.