In this paper, a simple method is described for visually demonstrating that the wavelength of light reduces when entering a medium of higher refractive index. When a violet laser (405 nm) is reflected off the surface of a Blu-ray disc (track spacing 320 nm) diffraction cannot occur since the wavelength is greater than the track spacing. However,…

Light spectrum dispersion is an exciting subject in science because of its beautiful atmospheric colour phenomenon which attracts students. However, to see the phenomenon is not easy since it needs a spectrometer, which is commonly expensive. Therefore, the present study aims to describe a low-cost spectrometer for investigating lighting spectrum…

The current pandemic era demands distance learning, including physics experiments on the topic of optics. One of the optical phenomena that needs to be explained in optic courses is fluorescence. This study offers a simple home experiment regarding the application of fluorescence, namely to identify the purity of olive oil using simple…

This work presents an experiment that seeks to simulate human color vision through electronic components in an attempt to build, together with the students, a cybernetic 'eye'. The limitation of the cybernetic eye developed here in relation to the standard human chromatic vision, which makes it a 'colorblind eye', is an argument to be explored by…

This paper demonstrates the use of smartphones in an experiment of light absorption and light scattering. The LED display and camera of the smartphone are used as the light source and as the detector, respectively. The color wheel is used to choose the color of the light source to be shone through the sample for analysis. The detector directly…

This study provides information about the formation of colours with an experimental activity based on the reflection of coloured lights from pigments. The activity shows the formation of colour in a simple and entertaining way. The lights are reflected by being changed by different coloured pigments. This activity provides an opportunity to…

In this article, a consecutive series of four hands-on experiments are recommended to teach the colors of paint/pigment and their mixtures. These activities, which are effective in learning about how to make a simple observation and help to build argument-based knowledge about colors, offer an integrated and innovative way of teaching colors of…

Water can exhibit many different colors due to a variety of physical properties. Here, we focus on some observable colors within very pure freshwater. We only treat the absorption of light due to electronic and ro-vibrational excitations and scattering due to refractive index fluctuations of the water and the respective consequences for the…

Ever since Newton's groundbreaking work on the composed nature of light, additive colour mixing (and its laws) are subject to the interest of physicists as well as other sciences. In this paper, we present a setup for simple lab or home experiments on additive colour mixing and the laws of colour mixing. Students use the screen of a laptop or…

This paper demonstrates the use of a smartphone as a low-cost multi-channel optical fibre spectrophotometer suitable for physics laboratory classes. A custom-designed cradle and structure support were fabricated using 3D printing. The plastic optical fibres were arranged and inserted into the hole of the cradle to guide the light to the rear…

Semiconductor materials are at the core of electronics. Most electronic devices are made of semiconductors. The operation of these components is well described by quantum physics which is often a difficult concept for students to understand. One of the intrinsic parameters of semiconductors is their bandgap energy E[subscript g]. In the case of…

This paper presents an experimental activity based on the absorption of light colours by pigments. The activity is constructed using a stepwise design and offers an opportunity for students and teachers to compare and generalize the interactions between light and pigment colours. The light colours composing an artificial rainbow produced in the…

Is moonlight "silver" or "cold"? In this paper we discuss the interesting combination of factors that contribute to the common descriptions of moonlight. Sunlight is reflected from the lunar surface and red-shifted. When traversing the atmosphere, moonlight is further depleted of short wavelength content by Rayleigh scattering.…

Teaching prismatic colours usually boils down to establishing the take-home message that white light consists of "differently refrangible" coloured rays. This approach explains the classical spectrum of seven colours but has its limitations, e.g. in discussing spectra from setups with higher resolution or in understanding the well…

What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called…