Physical Science Unit 5

Front 1

amplitude

Back 1

The maximum displacement of a wave's medium from its equilibrium point.

Front 2

crest

Back 2

The highest point on a wave.

Front 3

electromagnetic waves

Back 3

Waves formed by rapidly changing electric and magnetic fields and that require no medium.

Front 4

equilibrium position

Back 4

The position of a medium that's undisturbed; its resting position.

Front 5

frequency

Back 5

The number of wavelengths that pass by a particular point in space during a one-second interval.

Front 6

longitudinal wave

Back 6

A wave in which the medium is displaced in a direction parallel to the motion of the wave.

Front 7

mechanical waves

Back 7

Waves formed by disturbances in a physical medium.

Front 8

medium

Back 8

Material through which a wave travels.

Front 9

period

Back 9

The time it takes one complete wavelength to pass a given point.

Front 10

periodic wave

Back 10

A series of evenly timed disturbances in a medium.

Front 11

reciprocal

Back 11

A mathematical relationship in which a value, expressed as a fraction, can be turned into the other simply by flipping the fraction.

Front 12

speed of a wave

Back 12

The speed at which a wave travels.

Front 13

surface wave

Back 13

A wave that combines transverse and longitudinal motion.

Front 14

transverse wave

Back 14

A wave in which the medium is displaced in a direction perpendicular to the motion of the wave.

Front 15

trough

Back 15

The lowest point on a wave.

Front 16

wave

Back 16

A regular disturbance that moves either through a medium or space.

Front 17

wavelength

Back 17

The distance between successive compression peaks in a wave.

Front 18

wave pulse

Back 18

A single disturbance moving through a medium.

Front 19

absorption

Back 19

The transfer of wave energy into the medium, usually in the form of heat, when a wave reaches a boundary.

Front 20

antinodes

Back 20

The points of maximum displacement in a standing wave.

Front 21

boundary

Back 21

The interface between two different media.

Front 22

compression wave

Back 22

A longitudinal wave that propagates through a series of rarefactions and compressions of the medium.

Front 23

compressions

Back 23

The higher-pressure (denser) regions of sound waves.

Front 24

constructive interference

Back 24

When waves interfere to create a new wave amplitude larger than either of the original waves.

Front 25

decibel

Back 25

A unit used to measure sound intensity, or loudness, using a logarithmic scale based on the powers of 10.

Front 26

destructive interference

Back 26

When waves interfere to create a new wave amplitude smaller than either of the original waves.

Front 27

diffraction

Back 27

The change in direction of sound waves as the pass nearby objects and obstacles.

Front 28

echo

Back 28

The repeated occurrence of a sound, caused by the original sound wave and its reflection reaching the observer at different times.

Front 29

fundamental

Back 29

A standing wave in a string that has one antinode and zero nodes. It is the loudest-pitched sound of a plucked string.

Front 30

harmonics

Back 30

The overlapping standing waves of many different frequencies that occur in a string when it's plucked.

Front 31

in phase

Back 31

When two waves have amplitudes that are in the same direction.

Front 32

interference

Back 32

The superposition of two or more waves, resulting in a new wave pattern.

Front 33

principle of superposition

Back 33

When two or more waves meet, the result is a new wave whose amplitude is the sum of the amplitudes of all the individual waves.

Front 34

out of phase

Back 34

When two waves have amplitudes that are in opposite directions.

Front 35

nodes

Back 35

The points of minimum, or zero, displacement in a standing wave.

Front 36

pitch

Back 36

The "highness" or "lowness" of a sound, as directly to and determined by its frequency.

Front 37

rarefactions

Back 37

The lower-pressure (less dense) regions of sound waves.

Front 38

reflection

Back 38

The reversal of wave propagation direction when a wave reaches a boundary.

Front 39

refraction

Back 39

The transmission of a wave across a boundary, during which its frequency remains constant.

Front 40

reverberation

Back 40

The perceived elongation of a sound when the original sound wave and its reflection from a boundary reach the observer within 0.1 seconds of each other.

Front 41

standing wave

Back 41

A repeating wave pattern that has some number of stationary nodes and antinodes that can result from interfering waves.

Front 42

subsonic

Back 42

Slower than the speed of sound in a particular medium.

Front 43

supersonic

Back 43

Faster than the speed of sound in a particular medium.

Front 44

transonic

Back 44

Approximately the speed of sound in a particular medium. In air at room temperature, this is about 343 m/s.

Front 45

electromagnetic spectrum

Back 45

The entire range of electromagnetic radiation, from 0 Hz to more than 10^23 Hz.

Front 46

infrared

Back 46

Electromagnetic waves with frequency and energy just below the visible light spectrum.

Front 47

nanometer

Back 47

One billionth of a meter.

Front 48

pigment

Back 48

A substance used as coloring.

Front 49

primary colors

Back 49

Colors that aren't made up of any other colors. In pigments, the primary colors are magenta, cyan, and yellow. In light, they're red, green, and blue.

Front 50

prism

Back 50

A clear piece of glass used to separate white light into colors.

Front 51

secondary colors of light

Back 51

Colors formed by combining two primary colors of light.

Front 52

speed of light

Back 52

In a vacuum, the speed of light is 300,000 km/s (186,000 miles per second).

Front 53

ultraviolet

Back 53

Electromagnetic waves with frequency and energy just above the visible light spectrum.

Front 54

visible light

Back 54

Electromagnetic radiation having a wavelength between 380 and 750 nanometers.

Front 55

angle of incidence

Back 55

The angle the incident, or incoming, ray makes with the normal line.

Front 56

angle of reflection

Back 56

The angle the reflected ray makes with the normal line.

Front 57

concave lens

Back 57

A lens that's thicker at the edges than it is at the middle.

Front 58

concave mirror

Back 58

A mirror whose shiny side resembles the interior of a sphere.

Front 59

converging lens

Back 59

A lens that focuses parallel rays of light down to a single focal point.

Front 60

convex lens

Back 60

A lens that's thicker at the middle than at the edges.

Front 61

convex mirror

Back 61

A mirror whose shiny side resembles the exterior of a sphere.

Front 62

eyepiece

Back 62

In a microscope, the lens through which the observer looks.

Front 63

index of refraction

Back 63

A number that compares the speed of light in a given material to the speed of light in a vacuum.

Front 64

law of reflection

Back 64

When light hits a mirror, the angle of reflection equals the angle of incidence.

Front 65

law of refraction

Back 65

When light travels from a less dense material to a more dense material, it bends toward the normal.

Front 66

lens

Back 66

A transparent material, often made of glass, that's either thicker at its edge or thicker at its middle.

Front 67

microscope

Back 67

An optical instrument used for viewing enlarged images of very small objects.

Front 68

normal

Back 68

A line drawn perpendicular to a mirrored surface.

Front 69

objective

Back 69

In a microscope, the lens closest to the object being viewed.

Front 70

real

Back 70

An image, formed in a mirror or a lens, that's inverted and characterized by solid lines drawn on the ray diagram.

Front 71

telescope

Back 71

An optical instrument used for viewing distant objects.

Front 72

virtual

Back 72

An image, formed by a mirror or a lens, that's upright and characterized by the presence of dashed lines in the ray diagram.

Front 73

wave-particle duality

Back 73

The theory that light travels as both a wave and a series of particles at the same time.