Experiment 1: Dispersion of White Light
One of the classic experiments demonstrating the dispersion of white light into its component colors is the prism experiment, famously conducted by Sir Isaac Newton in the 17th century.
Procedure:
Newton used a glass prism and a small aperture to allow a beam of white sunlight to pass through.
The sunlight enters the prism and gets refracted (bent) as it passes through the glass, which has different refractive indices for different colors.
As a result of this differential refraction, the different colors making up white light are bent by varying amounts. This causes the colors to spread out into a spectrum, with violet light being refracted the most and red light the least.
Step-by-step explanation:
The phenomenon behind this experiment is known as dispersion. White light is actually a combination of all visible colors, each with a different wavelength. When white light enters a prism, the different colors have different speeds due to their differing wavelengths. This leads to different degrees of bending, causing the colors to spread out. This phenomenon can be explained using the principle of refraction and the dispersion relationship between the refractive index and wavelength of light.
Experiment 2: Recombination of Colors to Form White Light
Procedure:
This experiment can be demonstrated using a simple apparatus involving three primary colored lights: red, green, and blue. These colors are often referred to as the additive primary colors.
Place three separate light sources emitting red, green, and blue lights.
Project these colored lights onto a white screen or a blank wall, preferably in a dark room.
Adjust the intensity of each colored light to create a balance between them.
Step-by-step explanation:
This experiment showcases the principle of additive color mixing. In this scenario, when the three primary colors (red, green, and blue) are projected together onto a surface, they combine to create white light. This is because the additive mixing of colored lights involves adding the wavelengths of each color. Our eyes perceive white light when all the different wavelengths of the visible spectrum are present in roughly equal amounts.
This phenomenon is used extensively in various display technologies, such as computer monitors, television screens, and digital projectors. By manipulating the intensities of these primary colored lights, a wide range of colors can be generated on the display screen.
These two experiments highlight the properties of light and color, demonstrating how white light can be dispersed into its constituent colors through refraction and how different colors can be combined additively to recreate the perception of white light.