Summary
Highlights
Reflection occurs when light bounces off a surface, with the angle of incidence equal to the angle of reflection. Refraction is the bending of light as it passes from one transparent medium to another, such as from air to water. This bending happens because light changes speed in different mediums. This phenomenon explains why objects underwater appear closer and how prisms separate white light into its constituent colors, as different wavelengths bend at slightly different angles.
The additive primary colors are red, green, and blue. Combining these colors of light can produce white light. Our eyes have three types of color receptors, sensitive to red, green, and blue light, which allows us to perceive a wide range of colors based on their combinations. For example, combining red and green light produces yellow light, which is complementary to blue.
When mixing pigments or paints, the process is different from mixing light. Paints exhibit color due to the light they reflect. The subtractive primary colors are cyan, magenta, and yellow. When these are combined, they absorb all colors of white light, resulting in black. This principle is fundamental to how printing and art with pigments work.
The visible spectrum of electromagnetic waves ranges from red to violet, following the mnemonic ROYGBIV. The color of an object is determined by the wavelengths of light it reflects, not by an inherent color. For instance, a green leaf appears green because it reflects green light and absorbs other colors. Objects that absorb all visible light appear black, while those that reflect all wavelengths appear the color of the illuminating light.