How it all explodes!

Alfred Nobel made a fortune from manufacturing dynamite from nitroglycerine, and used his wealth to found a prize named after himself.

Original picture [Depositphotos]

If No­bel had also be­lieved in the heal­ing prop­er­ties of ni­tro­glyc­er­ine, this could have made his life eas­i­er. But as­sum­ing that this sub­stance only gave peo­ple headaches, the in­ven­tor of dy­na­mite suf­fered from heart dis­ease for a long time. In the hu­man body, ni­tro­glyc­er­ine caus­es the ni­tric ox­ide mol­e­cule, NO, to break down, mak­ing the blood ves­sels ex­pand. This prop­er­ty is used in the treat­ment of sev­er­al car­diac dis­eases, as it en­sures a full flow of blood to the heart. This was also the rea­son for the se­vere headaches among work­ers em­ployed in the man­u­fac­ture of ex­plo­sives, in­clud­ing at No­bel’s fac­to­ries. The struc­ture of ex­plo­sives is very di­verse, but in most cas­es these mol­e­cules con­tain ni­tro groups – small groups of atoms con­sist­ing of one atom of ni­tro­gen and two atoms of oxy­gen – NO₂ Of course, the an­cient Chi­nese could not have known these de­tails when they in­vent­ed gun­pow­der. Some of them were sim­ply lucky to live in ar­eas with soil rich in salts of al­ka­line met­als, where salt­peter (an im­por­tant com­po­nent of gun­pow­der) is found in its orig­i­nal form right on the sur­face of the ground. And gun­pow­der is a mix­ture of pul­ver­ized pieces of car­bon, sul­fur and salt­peter. When the mix­ture is heat­ed, the salt­peter breaks down. Potas­si­um ni­trate KNO₂ forms, along with oxy­gen O₂, which ig­nites the re­main­ing com­po­nents. Boom!


“The Walk­ing Dead” TV se­ries on АМС

The chem­i­cal re­ac­tion of the ex­plo­sion can be writ­ten down like this:

The let­ter “h” in brack­ets means that the sub­stance is a sol­id, and the let­ter “g” means it is a gas. All of the re­act­ing sub­stances are sol­id, but as a re­sult of the re­ac­tion eight gaseous mol­e­cules form: three mol­e­cules of hy­dro­gen diox­ide, three of car­bon monox­ide and two of ni­tro­gen. It is the hot ex­pand­ing gas­es form­ing in the swift com­bus­tion of the pow­er that push the can­non ball or bul­let. The form­ing solids of potas­si­um car­bon­ate and sul­fide scat­ter in the form of tiny par­ti­cles. They cre­ate the dense smoke that ac­com­pa­nies the ex­plo­sion of the gun­pow­der.



A large amount of heat is re­leased in any ex­plo­sion. This is be­cause mol­e­cules in the two parts of the re­ac­tion equa­tion have dif­fer­ent strength of bonds be­tween atoms. In the ex­plo­sion of the ni­tric com­pounds, the ex­treme­ly sta­ble ni­tro­gen mol­e­cule N2 is formed. The sta­bil­i­ty of this mol­e­cule comes from the triple bond that links the two ni­tro­gen atoms.

The sta­bil­i­ty of the triple bond means that a lot of en­er­gy is re­quired for an ex­plo­sion. Ac­cord­ing­ly, in the for­ma­tion of the triple bond, a large amount of en­er­gy is freed up, which is also what hap­pens in the ex­plo­sion.

An ex­plo­sion is a swift re­ac­tion. It is the speed that caus­es all the fa­tal con­se­quences. If the re­ac­tion took place slow­ly, the heat re­leased would dis­perse, and the gas­es would smooth­ly en­ter the en­vi­ron­ment, with­out caus­ing sig­nif­i­cant pres­sure and not cre­at­ing a shock wave. At­mo­spher­ic oxy­gen can­not en­ter the re­ac­tion swift­ly enough. So oxy­gen must be con­tained in the ex­plo­sive it­self. This is why ni­tric com­pounds, in which ni­tro­gen and oxy­gen are bond­ed to­geth­er, are of­ten ex­plo­sive.

Un­like gun­pow­der, where on ex­plo­sion a pres­sure of 6,000 at­mos­pheres aris­es in one thou­sandth of a sec­ond, in an ex­plo­sion of an equiv­a­lent amount of ni­tro­glyc­er­ine, a pres­sure of 270,000 at­mos­pheres is cre­at­ed in one mil­lionth of a sec­ond.

While gun­pow­der is com­par­a­tive­ly safe for use, ni­tro­glyc­er­ine be­haves ter­ri­bly un­pre­dictably. Ni­tro­glyc­er­ine is a very un­sta­ble mol­e­cule. It ex­plodes on heat­ing or shak­ing.

Nev­er­the­less, in the 19th cen­tu­ry the need for ni­tro­glyc­er­ine in­creased (es­pe­cial­ly in build­ing shafts and tun­nels), as its ad­van­tages over less pow­er­ful gun­pow­der be­came ob­vi­ous.

Tunnel on the Circum-Baikal Railway [Deposit Photos]

Al­fred Bern­hard No­bel, who by 1868 owned fac­to­ries in 11 coun­tries in Eu­rope and a com­pa­ny in San Fran­cis­co, be­gan to look for ways to sta­bi­lize ni­tro­glyc­er­ine with­out a loss of pow­er. It was log­i­cal to try to turn the un­pre­dictable liq­uid into a sol­id state. No­bel be­gan to ex­per­i­ment, mix­ing oily ni­tro­glyc­er­ine with neu­tral sol­id sub­stances – wood chips, ce­ment and char­coal dust. In the end, he de­cid­ed on kiesel­guhr – crumbly sil­i­ca with re­mains of di­atom­ic al­gae. It was some­times used for trans­port­ing ni­tro­glyc­er­ine as a pack­ag­ing ma­te­ri­al in­stead of wood­chips. Kiesel­guhr could ab­sorb leak­ing liq­uid ni­tro­glyc­er­ine, while re­main­ing por­ous. Tests showed that if liq­uid ni­tro­glyc­er­ine was mixed with kiesel­guhr (3:1), a thick paste with the den­si­ty of put­ty was formed. Kiesel­guhr sep­a­rat­ed the par­ti­cles of ni­tro­glyc­er­ine from one an­oth­er, and this re­duced the speed at which they broke down. This mix­ture could be giv­en any form, it did not break down and did not ex­plode on its own. Now the ex­plo­sion could be con­trolled. No­bel called the mix­ture of ni­tro­glyc­er­ine and kiesel­guhr dy­na­mite (from the Greek dy­namis – pow­er).

Controlled explosion of rock [Deposit Photos]

Ex­plo­sive ni­tro com­pounds are not used for mil­i­tary pur­pos­es. A mix­ture of salt­peter, sul­fur and char­coal was used in min­ing from the ear­ly 17th cen­tu­ry. Dy­na­mite helped to build a road through the Rocky Moun­tains of Cana­da, build the Pana­ma Canal with a length of 80 km, and de­stroy the un­der­ground moun­tain of Rip­ple Rock on the west­ern seaboard of North Amer­i­ca, which was a nav­i­ga­tion­al haz­ard. Ex­plo­sions lay the road for progress and free up space for new things. In the end, an ex­plo­sion may just be ter­ri­bly beau­ti­ful.


Con­trolled ex­plo­sion of a wa­ter­mel­on


‘Napoleon’s but­tons’ Penne Le Cou­teur & Jay Bur­re­son

Gun­pow­der, Dy­na­mite