Cave

A cave or cavern is a hollow place in the ground, especially a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground. The word cave can also refer to much smaller openings such as sea caves, rock shelters, and grottos.

Speleology is the science of exploration and study of all aspects of caves and the cave environment. Visiting or exploring caves for recreation may be called caving, potholing, or spelunking.

Types and formation

The formation and development of caves is known as speleogenesis. Caves are formed by various geologic processes and can be variable sizes. These may involve a combination of chemical processes, erosion from water, tectonic forces, microorganisms, pressure, and atmospheric influences.

It is estimated that the maximum depth of a cave cannot be more than 3,000 metres (9,800 ft) due to the pressure of overlying rocks. For karst caves the maximum depth is determined on the basis of the lower limit of karst forming processes, coinciding with the base of the soluble carbonate rocks.

Breathing

Breathing is the process that moves air in and out of the lungs, or oxygen through other respiratory organs such as gills. For organisms with lungs, breathing is also called ventilation, which includes both inhalation and exhalation. Breathing is one part of physiological respiration required to sustain life.Aerobic organisms of birds, mammals, and reptiles—require oxygen to release energy via cellular respiration, in the form of the metabolism of energy-rich molecules such as glucose. Breathing is only one of the processes that deliver oxygen to where it is needed in the body and remove carbon dioxide. Another important process involves the movement of blood by the circulatory system.Gas exchange occurs in the pulmonary alveoli by passive diffusion of gases between the alveolar gas and the blood in lung capillaries. Once these dissolved gases are in the blood, the heart powers their flow around the body (via the circulatory system). The medical term for normal relaxed breathing is eupnea.

Dragon's breath

Dragon's breath is a special type of incendiary-effect round for a 12 gauge (18.5 mm) shotgun. Dragon's breath consists primarily of magnesium pellets/shards. When the round is fired, sparks and flames can shoot out to about 100 feet (30 meters), although some sources claim it extends to 300 feet (91 meters). Dragons breath is normally chambered in 12 gauge 2 3/4" (18.5 mm × 69.9 mm) shot shell. The rounds are safe to fire out of an improved cylinder bore as well as a modified choke barrel, common on many shotguns.

Overview

While its actual professional combat or tactical usage remains undocumented, the visual effect it produces is impressive and entertaining, similar to that of a short-ranged flamethrower or fireworks, making it popular among gun enthusiasts. Also undocumented, it has been claimed by enthusiasts that the rounds are often used as a distress signal, similar to a very short duration emergency flare gun, though some would argue a flare would be better fitted for such. The round has also been used for intimidation purposes. It may also be used as a less-than-lethal option for self-/home-defense, though the less-than-lethal aspect and safety are disputed, as the magnesium shards burn at approximately 3,000 °F (1,650 °C), which is more than enough to light a person, or house on fire. Compared to most regular types of shotgun ammunition that is mass-produced, the pyrotechnic shell is somewhat expensive, and can cost anywhere between $5–7 (USD) per shell, depending on caliber and load. There is little or no record of its use in actual combat. Due to the shells being low-pressure charged rounds, it is not suited to be used in an auto-loading shotgun or semi-automatic shotgun; as it does not produce enough recoil energy to cycle the automated-action, causing the mechanism to fail to cycle.

Dragon's Breath Cave

The Dragon's Breath Cave is a cave located 46 kilometres (29 mi) northwest of Grootfontein in the Otjozondjupa Region of Namibia.

Inside this cave lies the largest non-subglacial underground lake in the world, with an area of almost 2 hectares (4.9 acres). The lake is located around 100 metres (330 ft) below the surface. Its total depth is unknown, though exploration to date suggests it is at least 100 m.

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Coordinates: 19°28′05″S 17°47′08″E / 19.46806°S 17.78556°E / -19.46806; 17.78556