Improvisation in engineering is to solve a problem with the tools and materials immediately at hand. Examples of such improvisation was the re-engineering of carbon dioxide scrubbers with the materials on hand during the Apollo 13 space mission, or the use of a knife in place of a screwdriver to turn a screw.
Improvised street bench in Naples
(Italy), made from wooden pallet
An improvised cowbell
, used for sheep or goats. The bell was found in 1988 in a field near Tuqu'
(Tekoa) in the West Bank. The bell's body is made of aluminum, probably a broken kitchen utensil, while the clapper is a brass cartridge case (SMI 25 NATO, probably 7.62×51mm).
Improvised hat cover of an Orthodox Jew on a rainy day in Tel Aviv
Engineering improvisations may be needed because of emergencies, embargo, obsolescence of a product and the loss of manufacturer support, or just a lack of funding appropriate for a better solution. Users of motor vehicles in parts of Africa develop improvised solutions where it is not feasible to obtain manufacturer-approved spare parts.
The popular television program MacGyver used as its gimmick a hero who could solve almost any problem with jury rigged devices from everyday materials, a Swiss Army knife and some duct tape.