Shock sensitivity is a comparative measure of the sensitivity to sudden compression (by impact or blast) of an

explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

. Determination of the shock sensitivity of a material intended for practical use is one important aspect of safety testing of explosives. A variety of tests and indices are in use, of which one of the more common is the Rotter Impact Test with results expressed as FoI ( Figure of Insensitivity.) At least four other impact tests are in common use, while various "gap tests" are used to measure sensitivity to blast shock.

Sensitivities vary widely

A few materials such as

nitrogen triiodide Nitrogen triiodide is an inorganic compound with the formula N I3. It is an extremely sensitive contact explosive: small quantities explode with a loud, sharp snap when touched even lightly, releasing a purple cloud of iodine vapor; it can even ...

cannot be touched at all without

detonating Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with s ...

, and so are of purely academic interest. Some other compounds with a high sensitivity to shock, such as

nitroglycerin Nitroglycerin (NG), (alternative spelling of nitroglycerine) also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive liquid most commonly produced by nitrating g ...

and acetone peroxide, may detonate from a firm jolt and so cannot be legally transported in pure form. Acetone peroxide is often used by amateurs and terrorists as a means to detonate other explosives as well as acting as the main blasting agent, often resulting in injuries or death to those who underestimate its sensitivity. A number of methods are known to desensitize nitroglycerine so that it can be transported for medical uses, and it is also incorporated into other less sensitive explosives, such as

dynamite Dynamite is an explosive made of nitroglycerin, sorbents (such as powdered shells or clay), and stabilizers. It was invented by the Swedish chemist and engineer Alfred Nobel in Geesthacht, Northern Germany, and patented in 1867. It rapidl ...

s and

gelignite Gelignite (), also known as blasting gelatin or simply "jelly", is an explosive material consisting of collodion- cotton (a type of nitrocellulose or guncotton) dissolved in either nitroglycerine or nitroglycol and mixed with wood pulp and saltp ...

s. Many practical commercial materials of intermediate sensitivity, such as gelignites and water gel explosives, can be safely handled as they will not explode from casual shocks such as being dropped or lightly knocked by a tool. However, they may explode if struck forcefully by a metal tool, and would certainly explode in the barrel if they were used in an artillery shell. Reliable initiation of such materials requires the small explosion of a

detonator A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electr ...

. Apart from this another explosive material such as

Armstrong's mixture Armstrong's mixture is a highly sensitive primary explosive. It is very friction-sensitive. Formulations vary, but one consists of 67% potassium chlorate, 27% red phosphorus, 3% sulfur, and 3% calcium carbonate. It is named for Sir William Armstr ...

is also used in commercial markets and even sold to the public in the form of

fireworks Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large number of devices ...

, cap guns and

party poppers A party popper is a handheld pyrotechnic device commonly used at parties. It emits a loud popping noise by means of a small friction-actuated explosive charge that is activated by pulling a string. The explosive charge comes from a very small amo ...

. Still less sensitive materials such as

blasting agent An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ...

s like ANFO, are so insensitive that the impulse from the detonator must be amplified by an

explosive booster {{unreferenced, date=August 2011 An explosive booster is a sensitive explosive charge that acts as a bridge between a (relatively weak) conventional detonator and a low-sensitivity (but typically high-energy) explosive such as TNT. By itself, the ...

charge to secure reliable detonation. Some polymer bonded explosives — especially those based on

TATB TATB, triaminotrinitrobenzene or 2,4,6-triamino-1,3,5-trinitrobenzene is an aromatic explosive, based on the basic six-carbon benzene ring structure with three nitro functional groups (NO2) and three amine (NH2) groups attached, alternating arou ...

— are designed for use in

insensitive munitions Insensitive munitions are munitions that are designed to withstand stimuli representative of severe but credible accidents. The current range of stimuli are shock (from bullets, fragments and shaped charge jets), heat (from fires or adjacent ther ...

, which are unlikely to detonate even if struck by another explosive weapon. Explosives {{Chem-stub