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 exp ...
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 ele ...
. 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, 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
dynamites and
gelignite
Gelignite (), also known as blasting gelatin or simply "j