?????? People have wondered about the nature of light and color since ancient times. Some people thought that light came from the eye rather than coming into the eye. To see, light was projected(投射) from our eyes to illuminate(照亮) things as we look at them. Now we know that what we see is mostly reflected light, like the light from the moon which is reflected sunlight. Light comes from a light source, such as the Sun, and either enters our eyes directly or after it has reflected off something.

????? In 1666, Sir Isaac Newton showed that when light passes through a prism, it separates into all the other colors. This clearly demonstrated that light is composed of many different colors. The difference between colors is due to their wavelength. A prism separates light into different colors because each color has different wavelength. The angle at which a color bends in a prism depends on its wavelength.

????? Colors with shorter wavelengths bend more than colors with longer wavelengths. This explains why red light bends less than yellow light. The reason is because its wavelength is longer. Of the visible colors, violet light has the shortest wavelength, so it bends the most.

????? If you have ever painted, you knew that different colors can be combined to create new colors. For example, if you add white to a color, you lighten it. However, the three primary colors, red, blue and yellow cannot be made by mixing other colors. It isn’t possible to mix any combination of colors to create red, blue or yellow. Mixing two primary colors creates a secondary color, such as purple, which is made by mixing blue and red. Mixing three primary colors create a tertiary (第三的)color such as brown or grey.

????? Color are wonderful to look at, but they also affect people in ways besides sight. They have a powerful effect on how people feel and behave. Artists know this and so do businesspeople who want to influence how people feel about their products and advertisement. For example, research has shown that people can be more productive if they are working in a blue room. The color purple is often linked to wealth and loyalty and is seem as a mysterious, spiritual(精神的) color. Some colors have even been associated with changes in blood pressure.

????? Though color can influence how we feel and act, these effects may depend on personal and cultural factors. Therefore, it’s important not to believe everything you hear about the effects of color. Though there are differences between cultures, there is a general agreement about some colors. The color red, for example, is a warm color associated with energy and excitement in many cultures. In china red is associated with fire, energy and good fortune. On the other hand, one experiment showed that exposing students to red before taking a test can have a negative effect. In fact, of all the colors, research shows that red has the most powerful effect on human behavior.

????? Certainly, it’s interesting and important to better understand the psychological effect of light and color. To gain a better understanding of these effects, more research is needed.