Speaker
Description
The phenomenon of light refraction can be easily observed and studied at schools concerning the relationship between the incident and the refraction angles of a laser beam, crossing the interface of two transparent media, leading to the concept of relative refractive index between the two media. A simple experimental setup with an ordinary protractor can provide a good accuracy for this physical property up to two decimal places, expressing the dependence of the refractive index with the characteristics of the medium. However, students also learn from the dispersion of light with an optical prism that this property depends on the frequency of the crossing light. External factors also influence the value of the refractive index such as the temperature of the medium. Thus, in any refractive index table the values provided are related to a specific wavelength of light (e.g., 589 nm – sodium D line) and temperature (e.g., room temperature).
In practice, the refractive index has a relatively weak dependence on wavelength and temperature, so the value variation occurs after the 2nd or 3rd decimal places. This means that a variation of 400 nm in frequency or 100 °C in temperature, results in a refraction angle variation of less than 0.6 degrees. Therefore, a more complex and accurate setup is required to measure the variation of the refraction angle which, usually, schools do not have.
In this work a Virtual Experimental Activity (VEA) is proposed to engage students in the study of reflection and refraction of light, as well as the refractive index dependence on wavelength and temperature for water based on a scientific paper from Bashkatov and Genina [1]. VEAs are computational pedagogical simulations designed to help students to develop experimental, conceptual and procedural skills [2] whereas studying a phenomenon with an experimental setup in a virtual environment. The exploration of a VEA takes into account the experimental errors coming from the virtual instruments and from the user’s dexterity.
In this simulation, the virtual instruments were designed to allow students to measure angles more accurately than usual, but without preventing them from introducing uncertainties into the measurements carried out, as it happens in a real experiment. We expect that the simulation will enhance the learning of the refractive index concept and, at the same time, develop in students essential skills that are so important in learning physics and science in general.
References
[1] A. N. Bashkatov, E. A. Genina, P.S. Water refractive index in dependence on temperature and wavelength: a simple approximation. In Saratov Fall Meeting 2002: Optical Technologies in Biophysics and Medicine IV, Valery V. Tuchin, Editor, Proc. of SPIE 5068 (2003).
[2] M. Rodrigues, P. S. Carvalho, P.S. Virtual Experimental Activities: a new approach. Physics Education, 57 (2022), 045025.
| Contribution categories - primary focus | Primary and secondary school |
|---|---|
| Contribution categories - type | Application (shared experience, activity suggestions) |
