Ch. 2

Front 1

wave

Back 1

disturbance that transfers energy from place to place

Front 2

energy

Back 2

the ability to do work

Front 3

medium

Back 3

The material through which a wave travels

Front 4

vibration

Back 4

repeated back-and-forth or up-and-down motion

Front 5

mechanical waves

Back 5

Waves that require a medium to travel through. They are produced when a source of energy causes a medium to vibrate

Front 6

properties of waves

Back 6

speed, amplitude, frequency, and wavelength

Front 7

crest

Back 7

the high point of a wave

Front 8

trough

Back 8

the low point of a wave

Front 9

amplitude

Back 9

The maximum distance that the particles of the medium carrying move away from their rest positions

Front 10

wavelength

Back 10

The distance between two corresponding parts of a wave

Front 11

frequency

Back 11

the number of complete waves that pass a given point in a certain amount of time

Front 12

hertz

Back 12

The unit that frequency is measured in

Front 13

electromagnetic wave

Back 13

Transfers electric and magnetic energy. Consists of vibrating electric and magnetic fields that move through space at the speed of light

Front 14

electromagnetic radiation

Back 14

the energy that is transferred through space by electromagnetic waves

Front 15

visible light

Back 15

Electromagnetic waves that you can see

Front 16

electromagnetic spectrum

Back 16

the complete range of electromagnetic waves placed in order from increasing frequency

Front 17

transparent

Back 17

transmits most of the light that strikes it

Front 18

translucent

Back 18

scatters light as it passes through, just as smoke, fog, and clouds scatter light as it passes through the air

Front 19

Opaque

Back 19

material reflects or absorbs all of the light that strikes it

Front 20

primary colors

Back 20

three colors that can combine to make any other color. when combined in equal amounts, the three primary colors of light, red, green, and blue, produce white light

Front 21

secondary color

Back 21

two primary colors combine in equal amounts to produce secondary color

Front 22

complementary colors

Back 22

Any two colors that combine to form white light

Front 23

pigments

Back 23

inks, paints, and dyes contain pigments

Front 24

reflection

Back 24

occurs when an object or wave bounces back off a surface through which it cannot pass

Front 25

law of reflection

Back 25

all waves obey the law of reflection

Front 26

plane mirror

Back 26

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

Front 27

image

Back 27

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

Front 28

virtual image

Back 28

the image you see in a plane mirror

Front 29

concave mirror

Back 29

a mirror with a surface that curves inward like the inside of a bowl

Front 30

optical axis

Back 30

imaginary line that divides a mirror in half

Front 31

focal point

Back 31

the point which rays paralleled to the optical axis meet or converge

Front 32

real image

Back 32

forms when rays actually meet

Front 33

convex mirror

Back 33

a mirror with a surface that curves outward

Front 34

refraction

Back 34

bending of light waves due to a change in speed

Front 35

lens

Back 35

curved piece of glass or other transparent material that refracts light

Front 36

convex lens

Back 36

or magnifying glass is thicker in the center than at the edges

Front 37

concave lens

Back 37

thinner in the center than at the edges

Front 38

cornea

Back 38

light enters the eye through the transparent front surface called the cornea

Front 39

pupil

Back 39

an opening through which light enters the inside of the eye

Front 40

iris

Back 40

a ring of muscle that contracts and expands to change the size of the pupil

Front 41

retina

Back 41

is a layer of cells that lines the inside of an eyeball

Front 42

rod

Back 42

contain a pigment that responds to small amounts of light

Front 43

cones

Back 43

respond to color. they detect red, green, or blue light.

Front 44

nearsighted

Back 44

person can see nearby objects clearly, but distant objects are blurry.

Front 45

farsighted

Back 45

person can see distant objects clearly, but nearby objects appear blurry.

Front 46

camera

Back 46

uses one or more lenses to focus light, and film to record an image.

Front 47

telescope

Back 47

forms enlarged images of distant objects. use combinations of lenses or mirrors to collect and focus light from distant objects

Front 48

refracting telescope

Back 48

consists of two convex lenses, one at each end of a tube

Front 49

objective

Back 49

gathers the light coming from an object and focuses the rays to form a real image.

Front 50

eyepiece

Back 50

magnifies the image so you can see it clearly.

Front 51

reflecting telescope

Back 51

uses a large concave mirror to gather light.

Front 52

microscope

Back 52

optical tool that makes small objects look larger. uses a combination of lenses to form enlarged images of tiny objects

Front 53

electron microscope

Back 53

use a beam of tiny particles called electrons instead of light to produce magnified image. They can take pictures of small objects