Prism demonstrating refraction and reflection effects. Beams of white light strike the prisms and are dispersed onto the opposite faces. At these faces, some of the light is refracted again, exiting the prism and forming the spectrum. The spectrum is a result of the different amounts of refraction of the different wavelengths of light present. In Isaac Newton's time, it was believed that white light was colourless, and that the prism itself produced the colour. The dispersed spectrum is the basis for spectroscopy, the study of visible light dispersed according to its wavelength, by a prism. During the early 1800s, Fraunhofer made experimental advances with dispersive spectrometers that enabled spectroscopy to become a more precise and quantitative scientific technique. Since then, spectroscopy has played and continues to play a significant role in chemistry, physics and astronomy.