Dynamite is an explosive material based on nitroglycerin, using diatomaceous earth (AmE: kieselgur; BrE: kieselguhr), or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued. Dynamite was invented by the Swedish chemist and engineer Alfred Nobel in Geesthacht, Germany, and patented in 1867. Its name was coined by Nobel from the Ancient Greek word δύναμις dýnamis, meaning "power".Dynamite is a high explosive, which means its power comes from detonation rather than deflagration. Dynamite is mainly used in the mining, quarrying, construction, and demolition industries, and it has had some historical usage in warfare. However the unstable nature of nitroglycerin, especially if subjected to freezing, has rendered it obsolete for military uses. Popular familiarity with dynamite led to metaphoric uses, such as saying that a particular issue is "political dynamite".Dynamite consists of three parts nitroglycerin, one part diatomaceous earth and a small admixture of sodium carbonate. This mixture is formed into short sticks and wrapped in paper. A blasting cap and fuse of any length are then inserted down the middle. Nitroglycerin by itself is a very strong explosive, and in its pure form it is extremely shock-sensitive (that is, physical shock can cause it to explode), and degrades over time to even more unstable forms. This makes it highly dangerous to transport or use in its pure form.Absorbed into diatomaceous earth or sawdust, nitroglycerin is less shock-sensitive. Over time, the dynamite will "weep" or "sweat" its nitroglycerin, which can then pool in the bottom of the box or storage area. (For that reason, explosive manuals recommend the repeated turning over of boxes of dynamite in storage.) Modern packaging helps eliminate this by placing the dynamite into sealed plastic bags, and using wax coated cardboard. Crystals will form on the outside of the sticks causing them to be even more shock, friction or temperature sensitive. This creates a very dangerous situation. While the risk of an explosion without the use of a blasting cap is minimal for fresh dynamite, old dynamite is dangerous.Dynamite is usually sold in the form of cylinders about 8 in (20 cm) long and about 1.25 in (3.2 cm) in diameter, with a weight of about 0.5 lb troy (0.186 kg). Other sizes also exist. The maximum shelf life of nitroglycerin-based dynamite is recommended as one year from the date of manufacture under good storage conditions.Another form of dynamite consists of nitroglycerin dissolved in nitrocellulose and a small amount of ketone. This form of dynamite is similar to cordite and gelignite, and is much safer than the simple mix of nitroglycerin and diatomaceous earth. Military dynamite achieves greater stability by avoiding the use of nitroglycerin and uses much more stable chemicals.