Light & Transparency
What are electromagnetic waves?
disruptions in an electromagnetic field produced by vibrating charged particles. They can travel through the vacuum of space, sometimes referred to as light or visible light.
What is the difference between luminous objects and illuminated objects?
luminous - an object that can produce visible light such as lamps, flashlights, and candles.
illuminated - an object that doesn't produce light, instead it reflects some light and this is how we see them.
What makes the color white?
A reflection of all the colors on the spectrum. White is not a single wavelength, but all wavelengths.
What are radio waves?
The longest EM waves. These operate cellphones and TVs.
What are gamma rays?
The shortest wavelengths. The highest energy waves emitted during radioactive decay. Used in medial treatment and astronomy
What is visible light?
The portion of the electromagnetic spectrum that is visible to humans
What is incandescence?
Light produced by objects that glow as a result of high temperature, such as old fashioned light bulbs.
What are the primary colors?
red, blue, green
What are microwaves?
A subsection of radio waves used for communication, navigation, and cooking
Study how colors mix on page 508-509. For example, what color is produced by mixing blue and red light?
what color is produced by mixing cyan and yellow?
magenta
green
What is a transparent material?
A material through which light can easily pass such as glass, cellophane and air.
What is fluorescence?
an object gives off light after absorbing electromagnetic energy.
What are the secondary colors?
The colors made by primary colors: yellow, magenta, cyan
What are infrared waves?
The waves just below the red wavelengths of visible light. Used for medical imaging and wireless devices (some animals can detect infrared waves)
How is black made?
when a substance absorbs all wavelengths of visible light.
What is a translucent material?
Materials that do not allow light to pass easily, though some light does pass so you see a dim image, but nothing detailed.
What is phospohorescence?
These objects also absorb electromagnetic energy, but slower than fluoroescence so they glow for a long time after absorbing energy.
What is a virtual image?
An image that appears to be equal distance away on the opposite side such as your reflection in a mirror. These images cannot be projected.
What are ultraviolet waves?
Waves just beyond the violet waves of the visible spectrum. Used for medical treatments and killing germs.
What is the purpose for the cones in human eyes?
The detect color.
What is an opaque material?
What is chemiluminescence and bioluminescence?
A chemical reaction that gives off energy in the form of light. When a living thing produce this kind of light, we call it bioluminescence.
What is a real image?
When rays of light come together by a focusing device such as a lens and form an image onto a surface. These images can be projected.
What are x-rays?
high energy waves that were accidentally discovered? Used for medical imagery, transportation security, and nondestructive inspection.
What is the difference between additive colors and subtractive colors?
Additive: blending wavelengths together to produce various hues, such as mixing equal amounts of red and blue to make magenta.
subtractive: pigments which absorb wavelengths, thereby removing some wavelengths of light.