At the end of registering the information obtained, the spectrum types are investigated, and the results are compared.The problem of interpretation of common provenance of the samples within the infrared spectra database of polypropylene samples from car body parts and plastic containers as well as Raman spectra databases of blue solid and metallic automotive paints was under investigation. Students are required to draw their observed spectra. Look for a place where there is natural or artificial light, but without pointing directly to the light source (for example, the Sun) and look through the small slit of 1cm located on the lid of the box.įor example, the student will use the spectrometer to investigate the spectrum of a white light lightbulb, a yellow light lightbulb, the Sun. Then proceed to open the matchbox a little at the end on the opposite side of the small slit previously made, see Figure 7.įigure 7: Preparing the matchbox for observation. Glue the piece of CD/DVD inside the matchbox, see Figure 6.įigure 6: Gluing the piece of CD/DVD inside the matchbox. Take a CD/DVD and then cut a piece with a radius of approximately 4 cm and an angle of 30 to 40º of arc, see Figure 5. See Figure 4įigure 4: Carving the small slit on the top of the matchbox. On the top of the box, carve a small slit approximately 1 cm high and 3 cm wide, leaving 7-8 mm free from the box end. The inside of the box is to be painted with marker or black vinyl, see Figure 3.įigure 3: Painting of the internal part of the matchbox. He projected the colours onto a wall after letting sunlight go through a narrow slit and a prism. The discovery that white light is a mixture of all colors was first made by Isaac Newton in 1666. Black results from the complete absence of light, while white light is a combination of all colors. For example, the color yellow is a blend of red and green, magenta is a mixture of red and blue, and cyan is a combination of green and blue. Finally, light at the upper end of the spectrum, with a wavelength of about 380 nm, is perceived as violet.Īll the other colours that we see are a mixture of red, green and blue. We perceive as red the light at the lower end of the visible spectrum (approximately 740 nm), while light in the middle of the visible spectrum is seen as green. This occurs thanks to specialised cells in our eyes, called cones. Our eyes perceive visible light as different colours, depending on the wavelength. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. Gamma-rays (wavelengths shorter than 1 picometer).Ī micrometer (also called a micron), a nanometer, and a picometer are one thousand, one million, and one billion times smaller than a millimeter, respectively.įigure 2: The spectrum of visible light as part of the whole electromagnetic spectrum.X-rays (wavelengths between approximately 1 picometer to 10 nanometers).Ultraviolet (UV) (wavelengths between approximately 10 and 100 nanometers).Visible light (wavelengths between approximately or 380 and 740 nanometers).Infrared (IR) (wavelengths of the order of 10 micrometers).Microwaves (wavelengths of the order of 1 cm).Radio waves (wavelengths greater than approximately 10 cm).This wide range of wavelengths, collectively referred to as the electromagnetic spectrum, is divided into seven distinct regions based on the wavelength decreasing and energy/frequency increasing order. Visible light is a form of electromagnetic radiation, which propagates through waves with varying wavelengths and frequencies, see Figure 2. Generally, visible light is defined as the wavelengths that are visible to most human eyes.įigure 1: An overview of the electromagnetic spectrum. Visible light is a form of electromagnetic (EM) radiation, as are radio waves, microwaves, infrared radiation, ultraviolet radiation, X-rays and gamma rays, see Figure 1. Visible light is the portion of the electromagnetic spectrum that can be detected by the human eye.
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