Light How do we see?

Light Wave

What is Light? Light is a form of energy that has the ability to cause change, such as heating an object. A combination of several different wavelengths of light traveling together is called white light. The visible spectrum is the band of light waves of different colors in the electromagnetic spectrum that vibrates at different frequencies our eyes can detect.

How does light travel? Just like sound, light travels in waves and some light is not detected by our eyes. A photon is a small particle of light that travels in a straight pathway. The color of light is determined by its wavelength. The color red has the longest wavelength. The color violet has the shortest wavelength. ROY G. BIV

Diffusion

How does it travel? Diffraction or Diffusion is breaking white light into its 7 component colors, the visible spectrum. Frequency is the amount of crests to pass a given point in space in one second. It is measured in Hertz. Peak is the highest point of the wave. Transmit means to allow light to pass through.

How does Light Travel? Light doesn’t need a medium or material to travel through. Light from the sun can travel 150 million km or 90 million miles to Earth in less than 8 ½ minutes. Light and sound have many ways they are similar and different. Can you give any examples?

Refraction

Reflection Vs. Refraction Reflection is the change in the direction of waves after they bounce off a surface. Refraction is the bending of light waves as they travel at an angle from one medium to another. When light waves absorb, they take in as heat. When you see color, all colors all are absorbed except the color you see.

Materials and Light Transparent materials let most light waves pass through. Ex. glass and transparency film Opaque materials let no light waves through. Ex. wood Translucent materials let some light waves pass through. Ex. frosted window glass

Prisms

Light Tools An optical tool that can be used to refract white light to see the visible spectrum is called a prism. A mirror is an optical tool that reflects images. A telescope is a optical tool that magnifies distant objects or makes them appear larger. Galileo made the 1st one in 1609. A microscope is an optical tool that magnifies images using light.

Light

Concave Lens

Convex Lens

Lens Lens is usually made from transparent glass or plastic. A light passes through a lens and it undergoes 2 refractions. Concave lenses will diverge or spread out light rays. It is thinnest at the center. Negative lens Convex lenses will converge or focus light to form an image. It is thickest at the center. Positive lens