The spectrograph: a prototype for a digital spectrometer

Abstract

Optical spectroscopy is a conceptual referent which links classical and modern Physics. This paper will consider how an educational path has to involve students in interpretative activities. Experiments can allow one to highlight the link between energy levels in atoms and discrete light emissions. After analysing several commercial devices and apps for mobile devices, our Physics Education Research Unit from Udine University (Italy) designed and created a digital spectrometer using a simple webcam and implemented the various functionalities which can be connected to PCs via USBs. Both hardware and software have been designed in order to obtain spectral images of various sources and the digitised spectrum. The hardware allows the use of different diffraction grating, coloured and optical filters and an optical goniometer, whilst the software is designed to allow calibration and qualitative and quantitative measures of wavelengths. We will describe this system in detail as well as some experimental activities which can be carried out by secondary school students and freshmen in biotechnology.