| A | B |
|---|
| Radiation | transfer of energy as electromagnetic waves |
| Electromagnetic wave | wave that has both electrical and magnetic properties and can travel in a vacuum |
| Electromagnetic spectrum | range of frequencies of radiation |
| Gamma | highest energy EM wave that is very dangerous to humans, used to kill cancer and sterilize medical equipment |
| X-rays | high energy EM wave that is dangerous to humans, used to see bones and hidden objects |
| Ultraviolet | high energy EM wave that is dangerous to humans, used in blacklights, and to kill bacteria and viruses |
| Visible light | EM wave that is made up of the colors of the rainbow |
| Infrared | low energy EM wave that is used in TV remotes, and makes heat images |
| Microwave | low energy EM wave that is used to cook food |
| Radio wave | low energy EM wave that is used to transmit TV, radio, and cell phone signals |
| Prism | device that bends the visible light rays into the light spectrum |
| Reflect | bouncing of waves off a surface |
| Refract | bending of waves when entering a new medium |
| Transparent | matter that transmits light straight through; examples air, water, clear glass |
| Translucent | matter that trasnmits light but scatters it so the image is fuzzy or blurry; examples tissue paper, lamp shade, frosted glass |
| Opaque | matter that does not let any light through; examples brick wall, wood, metal |
| Absorption | transfer of light energy into heat energy in the material |
| Reflection | bouncing of light waves off a surface |
| Refraction | bending of light waves when they enter a new medium |
| Scattering | light is sent in many different directions; clouds scatter the sun's light |
| Diffraction | bending of light around a barrier; like fuzzy edges of a shadow |
| Transmit | movement of light straight through a medium |
| Vacuum | absence of a medium; like outer space |
| Wavelength | distance from one point on a wave to an identical point on the next wave; from crest to crest or trough to trough on a transverse wave and compression to compression or rarefaction to rarefaction on a longitudinal wave |
| Crest | highest point on a transverse wave |
| Trough | lowest point on a transverse wave |
| Amplitude | measure of how far the particles in a transverse wave move above or below the midline; midline to crest or midline to trough |
| Frequency | how many wave cycles or wavelengths pass in a given amount of time |
| Virtual image | image produced when the light rays do not converge; can not be projected on a screen |
| Concave | curved inward; like the bowl of a spoon |
| Convex | curved outward; like the back of a spoon |
| Converge | where light rays come together at a focal point to create a real image |
| Diverge | where light rays spead apart from each other and create a virtual image |
| Real image | image produced when light rays converge at a focal point, image is upside down and can be projected on a screen |
| Lens | clear optical tool that refracts light |
| Mirror | tool that reflects light |
| Law of reflection | law that states that light reflects back at the same angle it hits the object |
| Normal line | imaginary line that is perpendicular to the surface of a mirror; light rays always reflect straight back at this spot on the mirror |
| Inverted | upside down |
| Cornea | part of the eye that light rays enter |
| Retina | part of the eye that light rays converge on to create an image |
| Nearsightedness | able to see near objects, far ways objects are fuzzy |
| Farsightedness | able to see far away objects, near objects are fuzzy |
| Incandescent light | device that produces visible light from very hot material |
| Fluorescent light | device that produces visible light from ultraviolet waves |
| LED | light-emitting diode that create one type of visible light when electricity runs through it |
| Laser | device that produces more concentrated and intense light of a very small range of wavelengths |
| Optical fiber | thin, transparent glass thread that transmits light over long distances |
| Color | difference in wavelenght along the visible light spectrum |
| Brightness | how bright or dim a light is due to its amplitude |
