New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

in the 1930s, farmers reportedly had trouble with exploding trousers as a result of attempts to control

ragwort ''Jacobaea vulgaris'', syn. ''Senecio jacobaea'', is a very common wild flower in the family Asteraceae that is native to northern Eurasia, usually in dry, open places, and has also been widely distributed as a weed elsewhere. Common names inc ...

, an agricultural

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

. Farmers had been spraying

sodium chlorate Sodium chlorate is an inorganic compound with the chemical formula Na ClO3. It is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 300 °C to release oxygen and leaves sodium chloride. Sever ...

, a government recommended weedkiller, onto the ragwort, and some of the spray had ended up on their clothes. Sodium chlorate is a strong oxidizing agent, and reacted with the organic fibres (i.e., the wool and the cotton) of the clothes. Reports had farmers' trousers variously smoldering and bursting into flame, particularly when exposed to heat or naked flames. One report had trousers that were hanging on a washing line starting to smoke. There were also several reports of trousers exploding while farmers were wearing them, causing severe burns. The history was written up by James Watson of

Massey University Massey University () is a Public university, public research university in New Zealand that provides internal and distance education. The university has campuses in Auckland, Palmerston North, and Wellington. Data from Universities New Zealand ...

in a widely reported article, "The Significance of Mr. Richard Buckley's Exploding Trousers" − which later won him an

Ig Nobel Prize The Ig Nobel Prize () is a satirical prize awarded annually since 1991 to promote public engagement with scientific research. Its aim is to "honor achievements that first make people laugh, and then make them think." The name of the award is a ...

On television

In their May 2006 "Exploding Pants" episode the popular U.S. television show ''

MythBusters ''MythBusters'' is a science entertainment television series created by Peter Rees (producer), Peter Rees and produced by Beyond International in Australia. The series premiered on the Discovery Channel on January 23, 2003. It was broadcast in ...

'' investigated the idea that trousers could explode based on the events of New Zealand in the 1930s. Experimenters tested four substances on 100% cotton overalls: * a paste comprising a mixture of

gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...

and water; * a "herbicide from the 1930s" which was sodium chlorate, a potentially explosive herbicide used at the time of the events; * a "fertilizer from the 1930s" which was

ammonium nitrate Ammonium nitrate is a chemical compound with the formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, but does not form hydrates. It is predominantly us ...

mixed with a liquid fuel (most likely

diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engine ...

, as an ammonium nitrate bottle, with the label facing the camera, was in the foreground of the shot, in the presence of a red plastic fuel can on the table); * gun cotton, the common name for nitrocellulose. Each of these were put to four different ignition methods:

flame A flame () is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction made in a thin zone. When flames are hot enough to have ionized gaseous components of sufficient density, they are then considered plasm ...

radiant heat Thermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. The emission of energy arises from a combination of electro ...

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...

, and

impact Impact may refer to: * Impact (mechanics), a large force or mechanical shock over a short period of time * Impact, Texas, a town in Taylor County, Texas, US Science and technology * Impact crater, a meteor crater caused by an impact event * Imp ...

. Although not naming "the herbicide" as

, they confirmed that trousers impregnated therewith would indeed vigorously combust upon exposure to flame, radiant heat, and impact, though their friction tests did not cause ignition. However,

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

(i.e. an

exothermic In thermodynamics, an exothermic process () is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e ...

chemical reaction between a

fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work (physics), work. The concept was originally applied solely to those materials capable of releasing chem ...

and an

oxidant An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or "Electron acceptor, accepts"/"receives" an electron from a (called the , , or ''electr ...

) is not the same as an

explosion An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated ...

, which involves a rapid increase in volume accompanied by the release of energy in an extreme manner (i.e. a

shock wave In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...

). Even so, a person witnessing such an event (especially if they were wearing the trousers) would likely describe such a sudden event as an explosion. The tests also revealed that none of the other three substances caused combustion of the trousers, thus indicating that sodium chlorate was probably a cause for the events that occurred.

On television

See also

References

Further reading