A Hollow Glass Prism is a laboratory instrument used to disperse white light into its constituent colors or wavelengths, creating a rainbow-like spectrum. It consists of a glass prism with a hollow center, allowing a light source to be passed through it. The prism refracts the light, causing it to bend as it passes through the glass, and the different colors or wavelengths of light bend at slightly different angles, causing them to separate and form a spectrum.

Hollow Glass Prisms are commonly used in optics experiments to study the properties of light and to demonstrate the phenomenon of dispersion, where the different colors of light are separated due to their different wavelengths. They are also used in spectroscopy to analyze the spectral characteristics of light emitted by various sources, such as stars, planets, or chemical compounds.