How Light Behaves Light is a form of energy that you can see when it interacts with matter. Lights travels in waves.

Parts of a Wave Crest – high point of wave Trough – low point of wave Resting point – halfway between a crest and a trough Wavelength – distance between one crest or trough and the next Amplitude – distance between resting point and crest or trough Think of wavelength as the length of a wave and amplitude as the height.

Light waves Travel in straight lines in all directions. Light waves travel until they strike an object. If the light waves cannot pass through an object, a shadow forms behind the object. A shadow is an area that is dark because light does not reach it – shadows form because an object blocks the light.

Behavior of Light Reflection occurs when light waves bounce off a surface. When we see an object, we are actually seeing light that the object reflects. Most surfaces reflect at least some of the light that hits them. Smooth surfaces reflect light in the same pattern – makes surfaces look shiny. Rough surfaces reflect light waves in many directions. Surfaces look dull.

Refraction is the bending of light waves as they pass from one material to another. Materials that can transmit and refract light include glass, water, and clear plastic. Refraction can make objects look bent or broken.

Absorbing Light Some materials absorb most of the light that hits them. You cannot see light that is absorbed because it is not reflected back to your eyes. When light waves are absorbed, the light energy changes to thermal energy. Dark colored objects absorb more light than light-colored objects.

Colors of Light The color of light depends on its wavelength. Red light has the longest wavelength, followed by orange, yellow, green, and blue light. Violet light has the shortest wavelength - Think of a rainbow! Sunlight consists of lights of all colors – light that is made up of all colors is called white light. Colors The color of an object depends on the color of light it reflects. A green object reflects green light and absorbs most other colors of light.

When white lights passes through a prism, light waves with shorter wavelengths bend more than light waves with longer wavelengths. As a result, a prism separates white light into all the colors of the rainbow. Raindrops acts like prisms when sunlight passes through them – this is how rainbows form!

Let’s Review! Light waves travel in straight lines in all directions away from a source. When light waves hit an object, they can be reflected, refracted, transmitted, or absorbed. White light is made up of all colors of light. A prism separates white light into these colors.