TNT equivalent
Encyclopedia
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
, i.e. metric ton) of TNT is a unit of energy
Units of energy
Because energy is defined via work, the SI unit for energy is the same as the unit of work – the joule , named in honour of James Prescott Joule and his experiments on the mechanical equivalent of heat...
equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT. The megaton is a unit of energy
Units of energy
Because energy is defined via work, the SI unit for energy is the same as the unit of work – the joule , named in honour of James Prescott Joule and his experiments on the mechanical equivalent of heat...
equal to 4.184 petajoules.
The kiloton and megaton of TNT have traditionally been used to rate the energy output, and hence destructive power, of nuclear weapon
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...
s (see nuclear weapon yield
Nuclear weapon yield
The explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene , either in kilotons or megatons , but sometimes also in terajoules...
). This unit is written into various nuclear weapon control treaties, and gives a sense of destructiveness as compared with ordinary explosives, like TNT. More recently, it has been used to describe the energy released in other highly destructive events, such as asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
impacts. However, TNT is not the most energetic of conventional explosives. Dynamite, for example, has more than 60% more energy density (approximately 7.5 MJ/kg, compared to 4.7 MJ/kg for TNT).
Value
A gram of TNT releases 4100–4602 JouleJoule
The joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
s upon explosion. To define the tonne of TNT, this was arbitrarily standardized by letting 1 gram TNT = 4184 J
Joule
The joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
(exactly). This conveniently defined the energy liberated by one gram to TNT as exactly one calorie
Calorie
The calorie is a pre-SI metric unit of energy. It was first defined by Nicolas Clément in 1824 as a unit of heat, entering French and English dictionaries between 1841 and 1867. In most fields its use is archaic, having been replaced by the SI unit of energy, the joule...
.
This definition is a conventional one. The explosive's energy is normally calculated using the thermodynamic work energy of detonation, which for TNT has been accurately measured at 4686 J/g from large numbers of air blast experiments and theoretically calculated to be 4853 J/g.
The measured pure heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
output of a gram of TNT is only 2724 J, but this is not the important value for explosive blast effect calculations.
A kiloton of TNT can be visualized as a cube of TNT of 8.46 metres on a side.
| Grams TNT | Symbol | Tons TNT | Symbol | Energy |
|---|---|---|---|---|
| gram of TNT | g | microton of TNT | μt | 4.184 J |
| kilogram of TNT | kg | milliton of TNT | mt | 4.184 J |
| megagram of TNT | Mg | ton of TNT | t | 4.184 J |
| gigagram of TNT | Gg | kiloton of TNT | kt | 4.184 J |
| teragram of TNT | Tg | megaton of TNT | Mt | 4.184 J |
| petagram of TNT | Pg | gigaton of TNT | Gt | 4.184 J |
Examples
- Conventional bombs yield range from less than 1 ton to MOABMoabMoab is the historical name for a mountainous strip of land in Jordan. The land lies alongside much of the eastern shore of the Dead Sea. The existence of the Kingdom of Moab is attested to by numerous archeological findings, most notably the Mesha Stele, which describes the Moabite victory over...
's 11 tonnes. - Minor ScaleMinor scaleA minor scale in Western music theory includes any scale that contains, in its tonic triad, at least three essential scale degrees: 1) the tonic , 2) a minor-third, or an interval of a minor third above the tonic, and 3) a perfect-fifth, or an interval of a perfect fifth above the tonic, altogether...
, a 1985 United States conventional explosion utilizing 4,400 tonnes of ANFOANFOANFO is a widely used bulk industrial explosive mixture. It consists of 94 percent porous prilled ammonium nitrate , that acts as the oxidizing agent and absorbent for the fuel — six percent Number 2 Fuel Oil...
explosive to simulate a 4 ktonTNT nuclear explosion, is believed to be the largest planned detonation of conventional explosives in history. - The Little BoyLittle Boy"Little Boy" was the codename of the atomic bomb dropped on Hiroshima on August 6, 1945 by the Boeing B-29 Superfortress Enola Gay, piloted by Colonel Paul Tibbets of the 393rd Bombardment Squadron, Heavy, of the United States Army Air Forces. It was the first atomic bomb to be used as a weapon...
atomic bomb dropped on HiroshimaHiroshimais the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshu, the largest island of Japan. It became best known as the first city in history to be destroyed by a nuclear weapon when the United States Army Air Forces dropped an atomic bomb on it at 8:15 A.M...
on August 6, 1945, exploded with an energy of about 15 ktonTNT. The nuclear weapons currently in the arsenal of the United States range in yieldNuclear weapon yieldThe explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene , either in kilotons or megatons , but sometimes also in terajoules...
from 0.3 ktonTNT to 1.2 MtonTNT equivalent, for the B83B83 nuclear bombThe B83 nuclear weapon is a variable yield gravity bomb developed by the United States in the late 1970s, entering service in 1983. With a maximum yield of 1.2 megatons, it is currently the most powerful atomic weapon in the US arsenal...
strategic bomb. - During the Cold WarCold WarThe Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
, the United States developed hydrogen bombs with a maximum theoretical yield of 25 MtonTNT; the Soviet UnionSoviet UnionThe Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
developed a prototype weapon, nicknamed the Tsar BombaTsar BombaTsar Bomba is the nickname for the AN602 hydrogen bomb, the most powerful nuclear weapon ever detonated. It was also referred to as Kuz'kina Mat , in this usage meaning "something that has not been seen before"....
, which was tested at 50 MtonTNT, but had a maximum theoretical yield of 100 MtonTNT. The actual destructive potential of such weapons can vary greatly depending on conditions, such as the altitude at which they are detonated, the nature of the target they are detonated against, and the physical features of the landscape where they are detonated. - The energy contained in 1 megaton of TNT (4.2 PJ) is enough power the average American household (in the year 2007) for 103,474 years. For example, the 30 MtonTNT estimated upper limit blast power of the Tunguska eventTunguska eventThe Tunguska event, or Tunguska blast or Tunguska explosion, was an enormously powerful explosion that occurred near the Podkamennaya Tunguska River in what is now Krasnoyarsk Krai, Russia, at about 7:14 a.m...
could power the aforementioned home for just over 3,104,226 years. To put that in perspective: the blast energy could power the entire United States for 3.27 days. - The total global nuclear arsenal is about 30,000 nuclear warheads with a destructive capacity of 5,000 megatons or 5 gigatons (5,000 million tons) of TNT.
- Megathrust earthquakeMegathrust earthquakeMegathrust earthquakes occur at subduction zones at destructive plate boundaries , where one tectonic plate is forced under another. Due to the shallow dip of the plate boundary, which causes large sections to get stuck, these earthquakes are among the world's largest, with moment magnitudes ...
s record huge MW values, or total energy released. The 2004 Indian Ocean Earthquake2004 Indian Ocean earthquakeThe 2004 Indian Ocean earthquake was an undersea megathrust earthquake that occurred at 00:58:53 UTC on Sunday, December 26, 2004, with an epicentre off the west coast of Sumatra, Indonesia. The quake itself is known by the scientific community as the Sumatra-Andaman earthquake...
released 9560 GtonTNT equivalent, but its ME (surface rupture energy, or potential for damage) was far smaller at 26.3 MtonTNT. - On a much grander scale, supernovaSupernovaA supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
explosions give off about 1044 joules of energy, which is about ten octillion (1028) megatons of TNT. - The approximate energy released when the largest fragment of Comet Shoemaker-Levy 9Comet Shoemaker-Levy 9Comet Shoemaker–Levy 9 was a comet that broke apart and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of solar system objects. This generated a large amount of coverage in the popular media, and the comet was closely observed by...
impacted JupiterJupiterJupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
was estimated to be equal to 6 million megatons (or 6 trillion tons) of TNT. - The maximum theoretical yield from 1 kg of matter would be produced by annihilating it with an equal amount of antimatterAntimatterIn particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles...
, converting all of the mass into energy. According to mass-energy equivalenceMass-energy equivalenceIn physics, mass–energy equivalence is the concept that the mass of a body is a measure of its energy content. In this concept, mass is a property of all energy, and energy is a property of all mass, and the two properties are connected by a constant...
, this reaction would produce a total of 2 × 8.99 J, which is equal to 42.96 Mt.
See also
- Nuclear arms raceNuclear arms raceThe nuclear arms race was a competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War...
- Orders of magnitude (energy)Orders of magnitude (energy)This list compares various energies in joules , organized by order of magnitude.-SI multiples:-See also:*Conversion of units of energy*Energies per unit mass*List of energy topics*Metric system*TNT equivalent*Scientific notation-Notes:...
- Relative effectiveness factorRelative effectiveness factorRelative effectiveness factor or R.E. factor is a measurement of an explosive's power for military demolitions purposes. It is used to compare an explosive's effectiveness relative to TNT by weight only. This enables engineers to substitute one explosive for another when they are calculating...
- TonTonThe ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
- TonneTonneThe tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...