Chapter Eighteen Review

Front 1

When light strikes an object it can be

Back 1

-reflected
-absorbed
-transmitted

Front 2

opaque

Back 2

a material that REFLECTS OR ABSORBS ALL OF THE LIGHT that strikes it [a door]

Front 3

transparent

Back 3

a material that TRANSMITS LIGHT that strikes it [a window]

Front 4

translucent

Back 4

a material that ALLOWS SOME LIGHT TO PASS THROUGH
[a frosted window]

Front 5

why do you see objects?

Back 5

because light reflects or bounces off of them

Front 6

regular reflection

Back 6

when parallel rays of light hit a smooth surface. All of the rays are reflected at the same angle. Like a reflection on a mirror or off smooth water

Front 7

rays

Back 7

straight lines used to represent light waves that show how light travels and reflects

Front 8

diffuse reflection

Back 8

when parallel rays of light hit a bumpy, or uneven, surface. light is scattered as each ray is reflected back at a different angle. like reflection off rippled water

Front 9

mirrors

Back 9

a sheet of glass that has a smooth, silver-colored coating on one side

Front 10

image

Back 10

a copy of an object formed by reflected or refracted rays of light

Front 11

plane mirrors [flat mirrors] what do they always produce?

Back 11

always produce a right-side up, or virtual image

Front 12

virtual images

Back 12

right side up or upright. "virtual" describes something that you can see, but does not really exist. The human brain assumes that the reflected light travels in a straight line. Even though they are reflected, the brain treats them as if they came from the other side of the mirror

Front 13

concave mirrors

Back 13

-surface curves inward
-can be a real or virtual image
-if object is further away from mirror than focal point a real image is produced

Front 14

real images

Back 14

formed when rays actually meet at a point. REAL IMAGES ARE UPSIDE DOWN OR INVERT

Front 15

convex mirrors

Back 15

-a mirror with a surface that curves outward [like back of a spoon]
-light rays that are reflected spread out
-rays never meet so the images are ALWAYS VIRTUAL

Front 16

refraction of light

Back 16

when light rays enter a new medium at an angle, the change in speed causes them to bend, or change direction

Front 17

index of refraction

Back 17

a measure of how much a ray of light bends when it enters a material

Front 18

prisms

Back 18

when light enters a prism, each wavelength is refracted by a different amount. this separated the colors of the visual light spectrum because of the different wavelengths

Front 19

rainbows

Back 19

-water droplets act like tiny prisms
-cause whit light to be separated in the colors of the visible spectrum

Front 20

mirages

Back 20

an image of a distant object caused by refraction of light

Front 21

lenses

Back 21

a curved piece of glass or other transparent material that is used to refract light
-lens refract light rays that pass through it

Front 22

concave lenses

Back 22

-thinner in the center
-parallel light rays that pass through are bent away from the center of the lens
-can only produce virtual image because light rays never meet

Front 23

convex lenses

Back 23

-thicker in the center
-as parallel light rays pass through the lens, they are bent towards the center of the lens
-the type of image formed depends on the position of the object in relation to the focal point [magnifying glass]

Front 24

what does the object's color depend on?

Back 24

the color of the light those objects reflect

Front 25

objects in white

Back 25

-reflect some colors and absorb the rest
-the colors that are reflected are seen as they enter the eye
-white objects reflect all the wavelengths of the color spectrum
-black objects absorb all the light

Front 26

objects in colored light

Back 26

-can affect how objects are seen
-the object appears the only color that it reflects
[ex. a red apple only reflects red light, so looking at a red apple with only green light will cause it to appear black since no red light is presented to be reflected]

Front 27

objects seen through filters

Back 27

some transparent materials only allow certain colors of light to pass through them. Like Christmas light that appear to be different colors because the glass they are made of, filters the light so only certain colors are allowed to pass through

Front 28

combining colors

Back 28

it is possible to produce any color by mixing colors of the spectrum in different amounts

Front 29

primary colors

Back 29

three colors used to make any other color

Front 30

secondary colors

Back 30

created when any two primary colors combined in equal amounts

Front 31

mixing colors of light

Back 31

primary colors of light
-red
-green
-blue
when combined in equal amounts they produce white light
yellow=red+green
cyan=green+blue
magenta=red+blue

Front 32

complementary colors

Back 32

a primary and secondary color can be used to make white.
yellow and blue
cyan and green
magenta and green

Front 33

mixing pigments

Back 33

different from mixing colors of light
-mixing primary colors of pigments will result in black
primary colors
-cyan
-yellow
-magenta

Front 34

pigments

Back 34

-substances that are used to color other materials
-they are opaque substances that reflect particular colors

Front 35

why do you see objects?

Back 35

you see objects because of a series of steps that involve the structures of the eye and the brain

Front 36

cornea

Back 36

the transparent front surface of the eye where light enters the eye

Front 37

iris

Back 37

a ring of muscle that contracts and expands to change the amount light entering the eye
-the colored part of the eye

Front 38

pupil

Back 38

-part of eye that looks black
-an opening in the center of the iris where light enters the eye

Front 39

lens

Back 39

-behind the cornea
-is convex
-muscles in the eye (ciliary muscles) contract and relax to make the lens longer and shorter to allow you to focus

Front 40

retina

Back 40

-the layer of cells lining the inside of the eye ball
-as the cornea and lens refract light an upside down image forms on the retina

Front 41

rods

Back 41

-contain a pigment that reacts to light
-used to see black, white and shades of gray

Front 42

cones

Back 42

-respond to colors
-only function in bright light
-there are three type that each detect one of the primary colors of light

Front 43

optic nerve and the brain

Back 43

short thick nerve that carries signals generated by the rods and cones to the brain

Front 44

correcting vision

Back 44

lenses can be used to refract light to correct vision when the eye is too long or too short

Front 45

nearsightedness

Back 45

-can see nearby things but distant objects are blurry
-occurs when eyeball is too long
-a concave lens is used to correct this(it spreads out the light so the image is formed farther back in the retina so that it is in focus

Front 46

farsightedness

Back 46

-can see distant things but nearby objects are blurry
-occurs when eyeball is too short
-corrected with convex lens(it focuses the light so that the image forms closer so that it is in focus when it hits the retina)