The color of an object is perceived as the color of light that is reflected by the object or transmitted by a solution. Regular white light has the full visible spectrum (approximately 380-760 nm). When light hits an object, the object absorbs some of the light waves and the rest of the light is reflected, making it vsible to the human eye. If light is transmitted through a solution, photons with a certain wavelength can be absorbed by species in the solution, the rest of the light is transmitted through it, which we can then observe.
To determine why solutions have different colors.