terms and definitions Flashcards
(231 cards)
1
Q
AC
A
alternating current
2
Q
Air Deck
A
A blasting technique where a column of air is left above the explosive charge by using a plug
3
Q
American Table of Distances
A
the quantity-distance table, for storage of explosive materials to determine safe distances from inhabited buildings, public highways, passenger railways, and other stored explosive materials
4
Q
Ammonium Nitrate
A
the ammonium salt of nitric acid and fuel oil
5
Q
Ampere
A
A unit of electrical Current produced by 1 volt acting through a resistance of one ohm
6
Q
ANFO
A
An explosive material consisting of Ammonium Nitrate and Fuel oil
7
Q
Approved, Approval, Authorized
A
given the ok by the authority having jurisdiction
8
Q
Artificial Barricade
A
An artificial mound or Revetted wall of earth of a minimum 3 foot thickness
9
Q
Authorized person
A
An Individual approved or signed by management to preform a specific duty/duties or to be at a specific location/locations
10
Q
Authority having Jurisdiction
A
The governmental agency, office or individual responsible for approving equipment, an installation, or a procedure
11
Q
Available Energy
A
The energy from an explosive material that is capable of preforming useful work
12
Q
Back Break
A
Rock broken beyond the limits of the last row of holes in the blast
13
Q
Ballistic Mortar
A
A lab instrument used for measuring the relative power of strength of an explosive material
14
Q
Base Charge
A
The main explosive charge in the base of the detonator
15
Q
Bench
A
A horizontal ledge in or at the top of a highwall from which holes are drilled vertically down into lifts
16
Q
Bench Height
A
The vertical distance from the top of a bench to the top of the next lower bench
17
Q
Black Powder
A
A low explosive compound of sulphur, charcoal, and an alkali nitrate usually potassium or sodium nitrate
18
Q
Blast/Blasting
A
The firing of explosive materials for such purposes as breaking rocker other material, moving material, or generating seismic waves; the assembly of explosive materials for such purpose
19
Q
Blast Area
A
The area of a blast within influence of flying rock missiles, gasses, and concussion
20
Q
Blast pattern
A
The plan of drill holes laid out on a bench; and expression of the burden distance and the spacing distance and their relationship to each other
21
Q
Blast site
A
The area where the explosive material is handled during loading, including the perimeter of the blast holes and 50 feet/ 15.24 meters in all directions from loaded holes or holes to be loaded
22
Q
Blaster
A
The qualified person in charge of and responsible for the loading and firing of a blast
23
Q
Blasting Accessories
A
non explosive devices and materials used in blasting ex… cap crimpers,tamping bags, blasting machines
24
Q
Blasting Agent
A
An explosive material that meets the prescribed criteria for insensitivity to initiation
Any material or mixture, consisting of fuel and oxidizer intended for blasting; cannot be detonated by means of a #8 test blasting cap when confined they need primers
25
Blasting Cap
A detonator that initiates the detonation of an explosive material and is initiated by a safety fuse
26
blasting crew
a group of persons who assist the blaster in loading, tying in and firing a blast
27
Blasting Galvanometer
An electrical resistance instrument designed specifically for testing electric detonators and circuits containing them:
to measure resistance or to check electrical continuity
28
Blasting log
A written record of info about a specific blast
as may be required by law or regulation
29
Blasting Machine
An electrical or electromechanical device that provides electrical energy for the purpose of energizing detonators in an electric blasting circuit
30
Blasting Mat
A mat constructed of various materials to cover blast holes for the purpose of preventing flying rock missles
like woven ,steel wire,Rope, Tires
31
Blasting vibrations
vibrations that are transmitted through the earth away from the immediate blast area
## Footnote
The energy from a blast that manifests itself in earth borne vibrations that are transmitted through the earth away from the immediate blast area
32
Block-Holing
The breaking of boulders by loading and firing small explosive charges in small diameter drilled holes
33
Booster
An explosive charge, used to improve the initiation of less sensitive explosive materials
## Footnote
to get it up to speed usually of high strength and high detonation velocity
34
Bootleg
The part of a drilled blast-hole that remains when the explosion does not break the rock to the bottom of the hole
35
Borehole(Blast-Hole)
a hole drilled in the material to be blasted, for the purpose of containing an explosive charge
36
Breakage
a term used to describe the size distribution of the rock fragments created by the blast
37
Bridge-wire
a resistance wire inside an electric detonator and is embedded in the ignition charge of the detonator
## Footnote
a resistance wire connecting the ends of the leg wires inside an electric detonator and which is embedded in the ignition charge of the detonator
38
Brisance
The shattering power of an explosive as distinguished from its total work capacity
39
Bulk mix
the mass of explosive material prepared for use in bulk form without packaging
40
Bulk mix delivery equipment
equipment that transports explosive materials in bulk form for mixing and/or loading directly into blast holes
41
Bulk Strength
The strength per unit volume of an explosive calculated from its weight strength and density
42
Bullet resistance
magazine walls or doors of construction resistant to penetration of a bullet of 150 grain M2 ball ammunition having a nominal muzzle velocity 2700ft/sec fired from a .30 calibre rifle from a distance of 100ft perpendicualr to the wall or door
43
bullet-sensitive explosive material
explosive material that can be detonated by 150 grain M2 ball ammunition having a nominal muzzle velocity of 2700 ft/sec fired from a .30 calibre rifle from a distance of 100ft
44
Burden
The distance from bore-hole to the nearest free face or the distance between bore holes measures perpendicular to the spacing
the total amount of material to be blasted by a given hole measured in cubic yards meters tons or tonnes
45
Cap sensitivity
The sensitivity of an explosive to initiation by a detonator
46
Cartridge
an individual closed shell, bag or tube of circular cross section containing explosive material
47
Cartridge count
the number of cartridges in a standard case
48
Cartridge punch
a wooden, plastic, or non sparking metallic device used to punch an opening in an explosive cartridge to accept a detonator or a section of detonating cord
| tool
49
Certified Blaster
A blaster Certified by governmental agency to prepare, execute, and supervise blasting
50
Class A explosives
explosives, that possess detonating or otherwise maximum hazard, like, but not limited to, dynamite, nitro-glycerine, blasting caps, and detonating primers
## Footnote
explosives, as defined by federal regulation, that possess detonating or otherwise maximum hazard, such as, but not limited to, dynamite, nitro-glycerine, blasting caps, and detonating primers
51
Class B Explosives
explosives, that possess flammable hazard such as, but not, limited to, propellant explosives, photographic flash powders, and some special fireworks
## Footnote
explosives, as defined by federal regulations, that possess flammable hazard such as, but not, limited to, propellant explosives, photographic flash powders, and some special fireworks
52
Class C explosives
explosives, that contain Class A or Class B explosives, or both, as components but in restricted quantities
| a and b= c
## Footnote
explosives, as defined by the federal regulations that contain Class A or Class B explosives, or both, as components but in restricted quantities
53
Collar
the term applied to the timbering or concrete around the mouth of the shaft
mouth or top of a drill hole
54
Column Charge
A charge of explosives in a blast hole in a form of a long continuous unbroken column
55
Column depth/Column Height
the length of each portion of a blast-hole filled with explosive materials
56
Commercial Detonation Velocity
The detonation velocity of an explosive material in a substantial container or Bore-hole
57
Commercial Explosives
Produced for industrial application rather than Military application
58
Confined wire
wire used to extend the firing lines or leg wires in an electric blasting circuit
59
Core load
the explosive core of detonating cord, expressed as Grains/foot
60
Critical Diameter
diameter of a cylindrical charge below which stable detonation cannot propagate
## Footnote
Minimum diameter for propagation of a detonation wave at a stable velocity
61
Current Leakage
portion of the firing current bypassing part of the blasting circuit through unintended paths
62
Cut-off
a break in a path of detonation or initiation caused by extraneous interference, such as fly-rock or shifting ground
63
Cushion Blasting
firing a single row of holes along a neat excavation line to shear rock between closely drilled holes, fired after production holes
64
Date shift Code
applied by manufacturers to the outside of shipping containers used to identify and trace the explosives
65
Dead pressing
desensitization of an explosive caused by pressurization
66
DC
Direct current
67
Decibel
the unit of air overpressure commonly used to measure airblasts
68
Deck Loading or Decking
a method of loading blast-holes in which the explosive charges, called decks or deck charges, in the same hole are separated by stemming or an air cushion
69
Decks
an explosive charge that is separated from other charges in the blast-hole by stemming or an air cushion
70
Deflagration
an explosive reaction that moves through an explosive material at a velocity less than the speed of sound
## Footnote
an explosive reaction such as a rapid combustion that moves through an explosive material at a velocity less than the speed of sound in the material
71
Delay
a pause of predetermined time between detonation or initiation impulses, to fire of explosive charges separately
## Footnote
distinct pause of predetermined time between detonation or initiation impulses, to permit the firing of explosive charges separately
72
Delay blasting
the practice of initiating individual explosive decks, bore-holes, or rows of bore-holes at predetermined time intervals using delay detonators, as compared to instantaneous blasting where all holes are fired essentially simultaneously
73
Delay Detonator
an electric or non-electric detonator used to introduce a predetermined lapse of time between the application of a firing signal and the detonation of the base charge
74
Delay Element
the device in a delay detonator that produces the predetermined delay between the application of a firing signal and detonation
75
Delay interval
the nominal time between the detonations of delay detonators or adjacent periods in a delay series; the nominal time between successive detonations and a blast
76
Delay period
a designation given to a delay detonator to show its relative or absolute delay time in a given series
77
Delay series
there are 2 types of delay series detonators designed to satisfy specific blasting requirements
millisecond (ms) with delay intervals in the order of milliseconds
long period (lp) with delay times in the order of seconds
78
Delay tag
a tag, band, or marker on a delay detonator that denotes the delay series, delay period, and/ or delay time of the detonator
79
Delay time
the lapse of time between the application of a firing signal and the detonation of the base charge of a delay detonator
80
Density
the mass of an explosive per unit of volume, usually expressed in grams per cubic centimetre or pounds per foot
81
Detonating cord
a flexible cord containing a center core of high explosive and used to initiate other explosives
82
Detonating cord Down-line
the section of detonating cord that extends within the blast-hole from the ground surface down to the explosive charge
83
Detonating Cord MS Connectors
non-electric, short-interval (millisecond) delay devices for use in delaying blasts that are initiated by detonating cord
84
Detonating Cord Trunk Line
the line of detonating cord that is used to connect and initiate other lines of detonating cord
85
Detonating Primer
the name applied for transportation purposes to a device consisting of a detonator and an additional charge of explosives, assembled as a unit
86
Detonation
an explosive reaction that moves through an explosive material at a velocity greater than the speed of sound in the material
87
Detonation pressure
the pressure produced in the reaction zone of a detonating explosive
88
Detonation velocity
the velocity at which the detonation progresses through an explosive
89
Detonator
any device containing any initiating or primary explosive that is used for initiating detonation
the term includes electric blasting caps, blasting caps for use with safety fuses, detonating cord delay connectors, and non-electric blasting caps
90
Drilling Pattern
the location of blast-holes in relationship to each other and/or the free face
91
Dynamite
a high explosive used for blasting, consisting essentially of a mixture of, but not limited to, nitro-glycerine, nitro-cellulose, ammonium nitrate, sodium nitrate and carbonaceous materials
92
Electric detonator
the detonator designed for, and capable of, initiation by means of an electric current
93
electrical storm
an atmospheric disturbance characterized by intense electrical activity, producing lightning strikes and strong electric and magnetic fields
94
Emulsion
an explosive material containing substantial amounts of oxidizers dissolved in water droplets, surrounded by an immiscible fuel
95
Energy
a measure of the potential for the explosive to do work
96
Explosion
a chemical reaction involving an extremely rapid expansion of gasses, usually associated with the liberation of heat
97
Explosive
any chemical compound, mixture, or device, the primary of common purpose of which is to function by explosion
98
Explosive Charge
the quantity of explosive material used in a blast hole, coyote tunnel, or explosive device
99
Explosive loading Factor
the amount of explosive used per unit of rock; also called Powder Factor
100
Explosive Materials
these include Class A B and C explosives, blasting agents, and detonators
101
Explosive oils
liquid sensitizers for explosives such as nitro-glycerine, ethylene glycol di-nitrate and metriol tri-nitrate
102
Explosive Strength
the amount of energy released by an explosive upon detonation
## Footnote
that is an indication of the capacity of the explosive to do work
103
Extra (Ammonia) Dynamite
a form of explosive that used ammonium nitrate as a substitute for nitroglycerin.
## Footnote
dynamite that derives a major portion of its energy from the reaction of a ammonium nitrate
104
Extraneous Electricity
electrical energy, other than actual fire and current or the test current from a blasting galvanometer, that is present at a blast site and that could enter an electrical blasting circuit; it includes stray current, static electricity, RF (electro-magnetic) waves, and time varying electric and magnetic field
105
Face
the end of an excavation towards which work is progressing or which was last done, open rock exposed to air
106
Fertilizer-grade ammonium nitrate
a grade of ammonium nitrate as defined by the fertilizer institute
107
Fire extinguisher rating
a rating set forth in the National Fire Code that may be identified by a number indicating the extinguishers relative effectiveness followed by a letter indicating the class or classes of fires for which the extinguisher has been found to be effective
108
fire resistant
Construction designed to offer reasonable protection against fire
109
firing current
an electric current of recommended magnitude and duration to sufficiently energize an electric detonator or a circuit of electric detonators
110
Flammability
the ease with which an explosive material may be ignited by flame and heat
111
Floor
bottom horizontal area where walking or excavation is done
112
flying rock
rocks propelled into the air by the force of an explosion but landing inside the blast area
113
Fly rock
rocks propelled beyond the blast area by the force of an explosion
114
Fragmentation
the breaking of a solid mass into pieces by blasting
115
Free face
a rock surface exposed to air or water that provides room for expansion upon fragmentation, sometimes called Open Face
116
Freezing
the semi-fusing and non-ejection of the pulverized rock or ore in the cut portion of a blasting round; generally caused by proving insufficient void space for the initial holes blasted in the cut, little or no delay between charges, and/or excessive charge weights
117
Fuel
a substance that may react with oxygen to produce combustion
118
Fumes
the gaseous products of an Explosion
for the purpose of fume classification, only poisonous or toxic gasses, such as carbon monoxide, hydrogen sulphide, and nitrogen oxides are considered
119
Fuse Cap / detonator
a detonator that is initiated by a safety fuse: also referred to as an ordinary blasting cap
120
Gap sensitivity
the maximum distance for propagation between standard charge sizes of explosive donor and acceptor
used for measuring the likelihood of sympathetic propagation
121
Gelatin Dynamite
a type of highly water-resistant dynamite characterized by its gelatinous propagation
122
Geology
a description of the types and arrangements of rock in the area
123
grains
a system of weight measurement where 7000 grains are equivalent to one standard 16 ounce pound (0.45kg)
124
Ground Fault
an electrical contact between part of the blasting circuit to the earth
125
Ground Vibration
shaking of the ground, by elastic waves emanating from a blast; usually measured in inches per second of particle velocity
126
Hang Fire
the detonation of an explosive after its designated time, dangerous
127
Hertz
a term used to express the frequency of ground vibration and air blast
128
High Explosives
explosives that are characterized by a very high rate of reaction, high pressure development and the presence of a detonation wave in the explosive
129
High wall
the bench, bluff or ledge of a surface excavation, usually in quarries and mines
130
Hydrostatic Pressure
the pressure of water at rest
131
Initiation
the act of causing an explosive material to detonate or deflagrate
132
initiator
a detonator or detonating cord used to start detonation in an explosive material
133
instantaneous detonator
a detonator that has a firing time of essentially 0 seconds as compared to the delay detonators with firing times from several milliseconds to several seconds
134
inventory
a listing of all explosive materials stored in a magazine
135
Jumbo
a machine with one or more mounted drills
136
Leg-Wires
the two single wires or one duplex wire extending out from an electric detonator
137
Liquid fuels
fuels in a liquid state
138
Loading
placing explosive material in a blast hole or against material to be blastedt
139
Loading Density
the weight of explosive loaded per unit length of bore-hole occupied by the explosive, expressed as pounds per foot or kilograms per meter of bore-hole
140
Loading Pole
non-metallic pole used to assist the placing and compacting of explosive charges in bore-holes
141
Low Explosives
explosives that are characterized by deflagration or a low rate of reaction of and the development of low pressure
142
Magazine
any building, structure, or container, other than an explosives manufacturing building, approved for the storage of explosive material
143
Magazine keeper
person responsible for the inventory and safe storage of explosive materials, including the proper maintenance of explosive materials, storage magazines, and areas
144
Main explosive charge
the explosive material that performs the major work of blasting
145
millisecond
1000th of a second
146
misfire
a blast that fails to detonate completely after an attempt at initiation; also the explosive material itself that failed to detonate as planned
147
Ms Connectors
non-electric, short-interval (millisecond) delay devices for use in delaying blasts that are initiated by detonating cord
148
Muck
the broken rock or ore displaced from its position in the earth by blasting or caving
149
Muck Pile
the pile of broken material resulting from a blast
150
Mud Capping
a mud-covered or unconfined explosive charge fired in contact with a rock surface without the use of a bore-hole
151
Nitro Glycerine
an explosive chemical compound used as a sensitizer in dynamite and represented by the formula C3H5 (ONO2)3
152
Number 8 test cap
the strength of detonator used to test explosives in a laboratory test
153
non electric detonator
a detonator that does not require the use of electric energy or safety fuse to function
154
non Sparking Metal
a metal that will not produce a spark when struck with other tools, rock, or hard surface
155
over burden
worthless material lying on top of a deposit of useful material
156
oxidizer or oxidizing Material
a substance, such as nitrate, that readily yields oxygen or other oxidizing substances to stimulate the combustion of organic matter or other fuel
157
Oxygen Balance
the percentage of oxygen in an explosive material that exceeds (plus) or is less than (minus) what is needed to produce the ideal reaction
158
parallel blasting circuit
nn electric blasting circuit in which the leg wires of each detonator are connected across the firing line directly or through bus-wires
159
particle velocity
a measure of intensity of ground vibration, specifically the time rate of change of the amplitude of ground vibrations
160
Parting
- a rock mass located between two seems of coal; a joint or crack in the rock
161
permissable
explosives having been approved for non-toxic fumes and allowed to be used under ground
162
PETN
an abbreviation for the name of the explosive, pentaerythritol tetra nitrate
163
Placards
signs placed on vehicles transporting hazardous materials (including explosive materials) indicating the nature of the cargo
164
Pneumatic Loading
he loading of explosive materials into a bore-hole using compressed air as the loading or conveying force
165
powder
any type of solid explosive used in blasting
166
Powder factor
the amount of explosive used per unit of rock; also called Explosive Loading Factor
167
Power source
the source of power for engineering electric blasting circuits, example a blasting machine or power line
168
Premature firing
the detonation of an explosive charge before the intended time
169
Pre splitting/preshear
a stress relief of a single row of holes drilled along a neat line where the detonation of explosives in the hole causes the shearing of a web in the rock between the holes
fired before production holes to produce a smooth wall
170
Prill
a small porous sphere of ammonium nitrate capable of absorbing more than 6% by weight of fuel oil
has a density of around 0.80 to 0.85 per cubic centimetre
171
Primary explosive
a sensitive explosive that nearly always detonates by simple ignition from such means as spark, flame, impact, friction, or other primary heat sources of appropriate magnitude
172
Primer
an explosive unit containing a suitable firing device used for the initiation of the entire explosive charge
173
Propagation
the detonation of explosive charges from a adjacent or nearby explosive charges
174
quarry
surface or open pit mine used for the extraction of rock
175
RAdio frequency energy
the energy transferred by electro-magnetic waves in the radio frequency spectrum
176
Radio frequency Transmitter
an electronic device that radiates radio frequency waves; the device may be fixed or mobile
177
Regulations
rules governing manufacturing transportation storgae sales posseion handling and use of explosive materials
## Footnote
Regulations promulgated (make known to the public)by Federal, State or local regulatory agencies governing the manufacture, transportation, storage, sale, possession, handling and use of explosive materials
178
Relief
he effective distance from a blast-hole to the nearest free face
179
Resistance
the measure of opposition to the flow of electrical current, expressed in ohms
180
saftey Fuse
a cord containing a core or black powder used to initiate blasting caps
181
Scaled distance
the ratio used to predict ground vibrations, scaled distance equals the distance from the blast to the area of concern, in feet or meters
182
Seam
a stratification plane in the sedimentary rock deposit, may also be sand or mud and run vertically or horizontally
183
Secondary Blasting
blasting to reduce the size of boulders resulting from a primary blast
184
seismograph
an instrument that measures and supplies a record of ground vibrations, also called a blast vibration monitor
185
Sensitivity
a physical characteristic of an explosive material classifying its ability to be initiated upon receiving an external pulse such as impact, shock, flame, friction, or other influences that can cause explosive decomposition; ability to propagate through the column of explosives
Low Sensitivity: column could be interrupted if there is a gap or an obstacle or water in the hole
High Sensitivity: may cause propagation between adjacent bore-holes
186
Shaped charge
an explosive with a shaped cavity specifically designed to produce a high velocity cutting or piercing jet of product reaction, usually lined with metal to create a jet of molten linear material
187
Shelf life
he length of time of storage during which an explosive material retains adequate performance characteristics
188
Shock wave
a transient pressure pulse that propagates at supersonic velocity
189
Short delay blasting
the practice of detonating blast-holes in successive intervals where the time difference between any two successive detonations is measured in milliseconds
190
Shot firer
the qualified person in charge of, and responsible for, the loading and firing of a blast (same as Blaster)
191
Shunt
the shorting together of the free ends of electric detonator leg-wires or the wire ends of an electric blasting circuit or part thereof
the name of an electrical shorting device applied to the free ends of electric detonators by the manufacturer
192
Slope
used to define the vertical rise of height to horizontal distance in describing the angle of a bench or face; example 1 ½ to 1 slope means there would be 1 ½ foot rise to each foot of horizontal distance
193
Slurry
an explosive material containing (lots of liquid), oxidizers and fuel plus a thickener
194
spacing
the distance between bore-holes
in bench blasting the distance is measured parallel to the free face and perpendicular to the burden
195
Specific gravity
the density of en explosive compared to water which is 1.0
196
Stability
the ability of an explosive material to retain chemical and physical properties specified by the manufacturer when exposed to specific environmental conditions over a particular period of time
197
Static Electricity
he electric charge at rest on a person or object
most often produced by the contact and separation of dissimilar insulating materials
198
Stemming
inert material used in the collar portion of the hole to confine the gaseous products formed in an explosion
199
Storage
he safe keeping of explosive materials, usually in specially designed structures called magazines
200
Strength
refers to the energy content of an explosion in relation to an equal amount of Anfo
201
Sub drill
to drill blast-holes beyond the planned grade lines or below floor level
202
Swell Factor
the ratio of the volume of material in its solid state to that when broken
203
Tamping
the action of compacting the explosive charge or the stemming in a blast-hole
204
TNT
Trinitrotoluene, a military compound used as a sensitizer in some slurries
205
Toe
in bench blasting, the distance from the free face to the blast-hole measured at the floor level of the bench
206
ENVIROMENT
Nature and surroundings that influence or are influenced by us
207
NATURE
The air water and land in or on which people animals and plants live
208
SURROUNDINGS
The conditions that you live or work in and the way that they influence how you feel or how effectively you can work
209
IMPACT
A powerful effect that something has on a situation or person
210
AQUIFER
An underground layer of water bearing permeable rock rock fractures or unconsolidated material
211
Hydrogeology
Study of water flow in aquifers and the characterization of aquifers
212
SURFACE WATER
Water located on top of the earths surface rivers creeks wetlands
213
LAKE
Any large bidy of slow moving or standing water that occupies an inland basin of good size
214
River
Natural stream of water of fairly large size flowing in definite course
215
Creek
A natural stream of water normally smaller and slower moving than a river
216
Swamp
A wetland often partially or intermittently covered in water with wooded vegetation
217
Marsh
A tract of low wet land often treeless
218
Air
A mixture of nitrogen oxygen and minute amounts of other gasses that surround earth
219
Atmosphere
The gas and aerosol evelope that extends from ocean land ice covered surfaceof a planet outward into space
220
Soil
Top layer of earths surface which plants can grow
221
Air blast
compressional waves which travel through the air resulting from an explosion
222
223
attenuation
gradual weakening or lessening in strength of seismic waves
224
blasting vibrations
energy from blast that transmits through earth by vibrations leaving the blast area
225
body waves
waves traveling through interior of the material
226
decibel
unit of air overpressure used to measure air blasts
227
displacement
actual distance particles move from their starting point during passage of a wave
228
elastic wave
seismeic wave that travels through the ground that displaces particles and then they return to their original position
229
longitudal wave
a wave that the direction of dispalcemnt is the same as direction of propagation
230
p waves
waves such as sound waves that media is deformed by compression or expansion in same direction the wave is traveling
231
Particle velocity
velocity at which the point moves as a wave passes through it
