89-490: A firecracker ( cracker , noise maker , banger ) is a small explosive device primarily designed to produce a large amount of noise, especially in the form of a loud bang, usually for celebration or entertainment; any visual effect is incidental to this goal. They have fuses, and are wrapped in a heavy paper casing to contain the explosive compound. Firecrackers, along with fireworks , originated in China . The predecessor of
178-573: A bunch, then red clay was spread at the bottom of the bunch and forced into each end of the firecracker with a punch; gunpowder was poured in, then the other end was sealed with an awl by turning the tube inward, and a fuse inserted. After India's National Green Tribunal (NGT) enacted a ban on the sale and use of crackers on Diwali festival in 2020, the Council for Scientific and Industrial Research (CSIR) developed green crackers made from cleaner raw materials which reduce emissions by suppressing
267-511: A celebratory event. They are legal, and anyone 18 and over can buy them without a licence. Vijayadashami and Diwali fireworks are a family event in many parts of India. People light up fireworks near their homes and in streets. Additionally, cities and communities have community fireworks. This custom may have begun on the Indian subcontinent after 1400 CE when gunpowder started being utilised in Indian warfare. India's first fireworks factory
356-420: A chemically pure compound, such as nitroglycerin , or a mixture of a fuel and an oxidizer , such as black powder or grain dust and air. Some chemical compounds are unstable in that, when shocked, they react, possibly to the point of detonation. Each molecule of the compound dissociates into two or more new molecules (generally gases) with the release of energy. The above compositions may describe most of
445-634: A degree of water resistance. Explosives based on ammonium nitrate have little or no water resistance as ammonium nitrate is highly soluble in water and is hygroscopic. Many explosives are toxic to some extent. Manufacturing inputs can also be organic compounds or hazardous materials that require special handling due to risks (such as carcinogens ). The decomposition products, residual solids, or gases of some explosives can be toxic, whereas others are harmless, such as carbon dioxide and water. Examples of harmful by-products are: "Green explosives" seek to reduce environment and health impacts. An example of such
534-402: A detailed description about the process and material used for making firecrackers at the end of the 19th century. At that time, firecrackers were made by women and children workers, using straw paper to make the body of the firecracker, while the fuse was made of paper imported from Japan made from the inner lining of the bamboo plant, or rice paper, stiffened with buckwheat paste. The bamboo paper
623-527: A few yellow and green colored Mandarin crackers were created and would be braided into the predominantly all-red strings to symbolize the emperor and the ruling class, while the numerous red crackers symbolized the common man. Once flash powder, which produces a significantly sharper and brighter bang, replaced black powder as a firecracker's explosive charge (circa 1924), manufacturers began competing to gain loyalty of typical consumers (that is, mainly boys 8 to 16 years old). Thousands of brands were created during
712-596: A firecracker ban to make sure that minimum health protocols will be observed during the new year celebration. A partial ban on firecrackers was imposed in March 1970 after a fire killed six people and injured 68. This was extended to a total ban in August 1972, after an explosion that killed two people. and an attack on two police officers attempting to stop a group from letting off firecrackers in February 1972. Since, in 2003,
801-640: A less loud, duller thud compared to modern flash-light crackers (which utilize a different explosive known as flash powder ). Mandarin crackers produced a dimmer, less brilliant flash when they exploded also. Individual Mandarin crackers were most often braided into "strings" of varying lengths, which, when ignited, exploded in rapid sequence. Generally, the strings (sometimes containing as many as several thousand crackers) would be hung from an overhead line before ignition. Most Mandarin crackers were colored all red and did not generally have designs or logos decorating their exterior surface (or "shell wraps"). Occasionally
890-433: A number of more exotic explosive materials, and exotic methods of causing explosions. Examples include nuclear explosives , and abruptly heating a substance to a plasma state with a high-intensity laser or electric arc . Laser- and arc-heating are used in laser detonators, exploding-bridgewire detonators , and exploding foil initiators , where a shock wave and then detonation in conventional chemical explosive material
979-611: A permit and part of a display by a licensed pyrotechnician. Tasmania , ACT and Northern Territory allow consumer use with a permit (dependent on calendar date). Northern Territory is the only part of Australia where a consumer does not require a permit, but this only applies on 1 July for Territory Day. Firecrackers are not authorized under the Explosives Act, thus making importation, possession, transportation, storage, or manufacturing illegal in Canada. The use of firecrackers
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#17327911934461068-468: A permit. The government of Norway banned the sale of rockets to individuals in early 2009, while allowing rockets to continue to be used in firework displays managed by licensed professionals. Other types of fireworks can still be sold. Fireworks and firecrackers are widely available throughout the Philippines and both Republic Act 7183 and Executive Order 28 were enacted to regulate and to control
1157-399: A physical shock signal. In other situations, different signals such as electrical or physical shock, or, in the case of laser detonation systems, light, are used to initiate an action, i.e., an explosion. A small quantity, usually milligrams, is sufficient to initiate a larger charge of explosive that is usually safer to handle. Glassine Glassine is a smooth and glossy paper which
1246-685: A practical measure, primary explosives are sufficiently sensitive that they can be reliably initiated with a blow from a hammer; however, PETN can also usually be initiated in this manner, so this is only a very broad guideline. Additionally, several compounds, such as nitrogen triiodide , are so sensitive that they cannot even be handled without detonating. Nitrogen triiodide is so sensitive that it can be reliably detonated by exposure to alpha radiation . Primary explosives are often used in detonators or to trigger larger charges of less sensitive secondary explosives . Primary explosives are commonly used in blasting caps and percussion caps to translate
1335-399: A reaction to be classified as a detonation as opposed to just a deflagration, the propagation of the reaction shockwave through the material being tested must be faster than the speed of sound through that material. The speed of sound through a liquid or solid material is usually orders of magnitude faster than the speed of sound through air or other gases. Traditional explosives mechanics
1424-512: A result of which the industry said it faced losses of Rs 1,000-crore and consequently layoffs. After India's National Green Tribunal (NGT) ordered a ban in the NCR region on the sale and use of crackers in 2020, the Council for Scientific and Industrial Research (CSIR) developed "green crackers" that used less polluting raw materials. Several states in India have either banned firecrackers or limited
1513-735: A smaller number are manufactured specifically for the purpose of being used as explosives. The remainder are too dangerous, sensitive, toxic, expensive, unstable, or prone to decomposition or degradation over short time spans. In contrast, some materials are merely combustible or flammable if they burn without exploding. The distinction, however, is not very clear. Certain materials—dusts, powders, gases, or volatile organic liquids—may be simply combustible or flammable under ordinary conditions, but become explosive in specific situations or forms, such as dispersed airborne clouds , or confinement or sudden release . Early thermal weapons , such as Greek fire , have existed since ancient times. At its roots,
1602-618: A thermodynamically favorable process in addition to one that propagates very rapidly. Thus, explosives are substances that contain a large amount of energy stored in chemical bonds . The energetic stability of the gaseous products and hence their generation comes from the formation of strongly bonded species like carbon monoxide, carbon dioxide, and nitrogen gas, which contain strong double and triple bonds having bond strengths of nearly 1 MJ/mole. Consequently, most commercial explosives are organic compounds containing –NO 2 , –ONO 2 and –NHNO 2 groups that, when detonated, release gases like
1691-709: Is mining . Whether the mine is on the surface or is buried underground, the detonation or deflagration of either a high or low explosive in a confined space can be used to liberate a fairly specific sub-volume of a brittle material (rock) in a much larger volume of the same or similar material. The mining industry tends to use nitrate-based explosives such as emulsions of fuel oil and ammonium nitrate solutions, mixtures of ammonium nitrate prills (fertilizer pellets) and fuel oil ( ANFO ) and gelatinous suspensions or slurries of ammonium nitrate and combustible fuels. In materials science and engineering, explosives are used in cladding ( explosion welding ). A thin plate of some material
1780-427: Is a pure substance ( molecule ) that in a chemical reaction can contribute some atoms of one or more oxidizing elements, in which the fuel component of the explosive burns. On the simplest level, the oxidizer may itself be an oxidizing element , such as gaseous or liquid oxygen . The availability and cost of explosives are determined by the availability of the raw materials and the cost, complexity, and safety of
1869-411: Is air-, water-, and grease-resistant. It is usually available in densities between 50–90 g/m (0.010–0.018 lb/sq ft). It is translucent unless dyes are added to the paper to color it or make it opaque . It is manufactured by supercalendering : after pressing and drying, the paper web is passed through a stack of alternating steel-covered and fiber-covered rolls called a supercalender at
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#17327911934461958-402: Is an important consideration in selecting an explosive for a particular purpose. The explosive in an armor-piercing projectile must be relatively insensitive, or the shock of impact would cause it to detonate before it penetrated to the point desired. The explosive lenses around nuclear charges are also designed to be highly insensitive, to minimize the risk of accidental detonation. The index of
2047-440: Is an important element influencing the yield of the energy transmitted for both atmospheric over-pressure and ground acceleration. By definition, a "low explosive", such as black powder, or smokeless gunpowder has a burn rate of 171–631 m/s. In contrast, a "high explosive", whether a primary, such as detonating cord , or a secondary, such as TNT or C-4, has a significantly higher burn rate about 6900–8092 m/s. Stability
2136-520: Is based on the shock-sensitive rapid oxidation of carbon and hydrogen to carbon dioxide, carbon monoxide and water in the form of steam. Nitrates typically provide the required oxygen to burn the carbon and hydrogen fuel. High explosives tend to have the oxygen, carbon and hydrogen contained in one organic molecule, and less sensitive explosives like ANFO are combinations of fuel (carbon and hydrogen fuel oil) and ammonium nitrate . A sensitizer such as powdered aluminum may be added to an explosive to increase
2225-443: Is created by laser- or electric-arc heating. Laser and electric energy are not currently used in practice to generate most of the required energy, but only to initiate reactions. To determine the suitability of an explosive substance for a particular use, its physical properties must first be known. The usefulness of an explosive can only be appreciated when the properties and the factors affecting them are fully understood. Some of
2314-452: Is evaluated by a tailored series of tests to assess the material for its intended use. Of the tests listed below, cylinder expansion and air-blast tests are common to most testing programs, and the others support specific applications. In addition to strength, explosives display a second characteristic, which is their shattering effect or brisance (from the French meaning to "break"). Brisance
2403-472: Is important in determining the effectiveness of an explosion in fragmenting shells, bomb casings, and grenades . The rapidity with which an explosive reaches its peak pressure ( power ) is a measure of its brisance. Brisance values are primarily employed in France and Russia. The sand crush test is commonly employed to determine the relative brisance in comparison to TNT. No test is capable of directly comparing
2492-400: Is placed atop a thick layer of a different material, both layers typically of metal. Atop the thin layer is placed an explosive. At one end of the layer of explosive, the explosion is initiated. The two metallic layers are forced together at high speed and with great force. The explosion spreads from the initiation site throughout the explosive. Ideally, this produces a metallurgical bond between
2581-939: Is regulated by the Law on Explosive Substances and the Production and Trading of Weapons ( Croatian : Zakon o eksplozivnim tvarima te proizvodnji i prometu oružja ). According to the Law, firecrackers (including other pyrotechnic articles) are divided into three classes: Class 1 Pyrotechnics - pyrotechnic articles for fireworks which represent a very low risk, have negligible noise level and are intended for use in restricted areas, including fireworks intended for use within residential buildings; Class 2 and 3 Pyrotechnics - pyrotechnic articles for fireworks which represent low to medium risk, have medium to high noise level and are intended for outdoor use in restricted areas and large open areas. Class 1 Pyrotechnics can be sold all year round to people over
2670-473: Is the ability of an explosive to be stored without deterioration . The following factors affect the stability of an explosive: The term power or performance as applied to an explosive refers to its ability to do work. In practice it is defined as the explosive's ability to accomplish what is intended in the way of energy delivery (i.e., fragment projection, air blast, high-velocity jet, underwater shock and bubble energy, etc.). Explosive power or performance
2759-411: Is the lead-free primary explosive copper(I) 5-nitrotetrazolate, an alternative to lead azide . Explosive material may be incorporated in the explosive train of a device or system. An example is a pyrotechnic lead igniting a booster, which causes the main charge to detonate. The most widely used explosives are condensed liquids or solids converted to gaseous products by explosive chemical reactions and
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2848-508: Is the only state that prohibits fireworks in any form. In 2007, New York City lifted its decade-old ban on firecrackers, allowing a display of 300,000 firecrackers to be set off in Chinatown 's Chatham Square . Under the supervision of the fire and police departments, Los Angeles regularly lights firecrackers every New Year's Eve, mostly at temples and the shrines of benevolent associations. The San Francisco Chinese New Year Parade,
2937-502: Is used as an inexpensive weighing paper . It is applied in foodservice as a barrier between strips of products (for example: meat, baked goods ). Glassine is resistant to grease and facilitates separation of individual foodstuffs. Glassine has been recommended for protecting the surface of stored acrylic paintings. However, glassine will adhere to soft (not completely cured) and medium-rich paint, especially when stored for an extended period of time and it may cause permanent damage to
3026-407: Is used to describe an explosive phenomenon whereby the decomposition is propagated by a shock wave traversing the explosive material at speeds greater than the speed of sound within the substance. The shock front is capable of passing through the high explosive material at supersonic speeds — typically thousands of metres per second. In addition to chemical explosives, there are
3115-880: Is usually the manufacture, sale, storage, and use of firecrackers that are subject to laws, including safety requirements for manufacture, the requirement of a permit to sell or store, or restrictions on the use of firecrackers. Firecrackers are commonly used in celebration of holidays or festivals, such as Halloween , Independence Day (also known as the Fourth of July) in the United States, Diwali in India , Eid al-Fitr in Southeast Asia , Tihar in Nepal , Day of Ashura in Morocco , Guy Fawkes Night or Bonfire Night in
3204-624: The Calcutta High Court on firecrackers (green firecrackers included) throughout the state of West Bengal for the 2021 Vijayadashami and Diwali festivities. The ban extends to all remaining festivals in the year, such as, Chhath Puja , Kali Puja , Guru Nanak Jayanti , Christmas and New Year's. Firecrackers and fireworks are generally forbidden in public during the Chinese New Year, especially in areas with significant non-Chinese populations, to avoid conflict between
3293-638: The Singapore Tourism Board . Other occasions where firecrackers are allowed to be set off are determined by the tourism board or other government organisations. Private sale and importation of fireworks and firecrackers is prohibited. Only rocket-type fireworks and small firecrackers are currently allowed in Sweden. The ban of firecrackers was effectuated by the EU Parliament and Swedish government effective 1 December 2001, but in 2006
3382-465: The government allowed firecrackers to be set off during the festive season, but only by government approved and appointed personnel. As such, private individuals are still prohibited from setting off fireworks and firecrackers. At the Chinese New Year light-up in Chinatown , at the stroke of midnight on the first day of the Lunar New Year, firecrackers are set off under controlled conditions by
3471-498: The Czech Republic. They can have up to 5g of flash powder and can be bought by anyone older than 21 years. For stronger firecrackers (up to 100g) a permit is required. Fireworks are classified. Some fireworks are restricted to adults (18 years), may be sold to private persons only on three days before New Year's Eve and may be used only on New Year's Eve or New Year (special permits can be obtained to use these on other days of
3560-583: The EU Parliament changed the laws, allowing smaller types of firecrackers. By 2008, the law had to be in effect in all EU member countries, including Sweden. Firecrackers have been banned in urban areas of Taiwan since 2008, but are still allowed in rural areas. In 1997, firecrackers became illegal, but most other consumer fireworks are legal. According to Reader's Digest , as of June 2023 49 states plus Washington, D.C. allow consumer fireworks to some degree. The types allowed vary by state. Massachusetts
3649-820: The United Kingdom, Halloween in Ireland, Bastille Day in France, Spanish Fallas , in almost every cultural festival of Sri Lanka (e.g. Sri Lankan New Year ), New Year's Eve and New Year's Day , and in the celebration of Chinese New Year by Chinese communities around the world. The use of firecrackers, although a traditional part of the celebration, has over the years led to many injuries and deaths. There have been incidents every year of users being blinded, losing body parts, or suffering other injuries, especially during festivities that customarily involve firecrackers such as Chinese New Year season. Hence, many governments and authorities have enacted laws completely banning
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3738-413: The aforementioned (e.g., nitroglycerin , TNT , HMX , PETN , nitrocellulose ). An explosive is classified as a low or high explosive according to its rate of combustion : low explosives burn rapidly (or deflagrate ), while high explosives detonate . While these definitions are distinct, the problem of precisely measuring rapid decomposition makes practical classification of explosives difficult. For
3827-418: The age of 14 in general stores and newsstands, while Class 2 and 3 Pyrotechnics can only be sold between 15 December and 1 January each year at gun shops and stores with special permits to the people over the age of 14 (class 2) or over the age of 18 (class 3). Use of Class 2 and 3 Pyrotechnics is allowed only in the period between 27 December and 1 January. Each year since 1993, between 15 December and 8 January,
3916-479: The capacity of an explosive to be initiated into detonation in a sustained manner. It is defined by the power of the detonator which is certain to prime the explosive to a sustained and continuous detonation. Reference is made to the Sellier-Bellot scale that consists of a series of 10 detonators, from n. 1 to n. 10 , each of which corresponds to an increasing charge weight. In practice, most of
4005-777: The celebration, leading to accidents. Firecrackers and fireworks were banned in Hong Kong for security reasons in 1967, as a result of many IED attacks in the 1967 Leftist Riot . However, the government stages a fireworks display in Victoria Harbour for New Year countdown and the second day of the Chinese New Year. Firecrackers are banned in Hungary since 2005. Other types of consumer fireworks are only allowed to be sold and used on New Year's Eve. Many people smuggle firecrackers from Slovakia, where they are legal. Firecrackers are easily available in India and are used to mark
4094-486: The chemical reaction moves faster through the material than the speed of sound ) are said to be "high explosives" and materials that deflagrate are said to be "low explosives". Explosives may also be categorized by their sensitivity . Sensitive materials that can be initiated by a relatively small amount of heat or pressure are primary explosives and materials that are relatively insensitive are secondary or tertiary explosives . A wide variety of chemicals can explode;
4183-425: The choice being determined by the characteristics of the explosive. Dependent upon the method employed, an average density of the loaded charge can be obtained that is within 80–99% of the theoretical maximum density of the explosive. High load density can reduce sensitivity by making the mass more resistant to internal friction . However, if density is increased to the extent that individual crystals are crushed,
4272-421: The development of pressure within rounds of ammunition and separation of mixtures into their constituents. Volatility affects the chemical composition of the explosive such that a marked reduction in stability may occur, which results in an increase in the danger of handling. The introduction of water into an explosive is highly undesirable since it reduces the sensitivity, strength, and velocity of detonation of
4361-531: The end of the paper machine so that the paper fibers are oriented in the same direction. Glassine is most commonly used as a base for further silicone coating for the manufacture of release liner . Glassine is also used as an interleaving paper in bookbinding , especially to protect fine illustrations from contact with facing pages; the paper can be manufactured with a neutral pH and can prevent damage from spilling, exposure, or rubbing. Glassine adhesive tape has been used in book repair. In chemistry , glassine
4450-498: The energy of the detonation. Once detonated, the nitrogen portion of the explosive formulation emerges as nitrogen gas and toxic nitric oxides . The chemical decomposition of an explosive may take years, days, hours, or a fraction of a second. The slower processes of decomposition take place in storage and are of interest only from a stability standpoint. Of more interest are the other two rapid forms besides decomposition: deflagration and detonation. In deflagration, decomposition of
4539-604: The energy released by those reactions. The gaseous products of complete reaction are typically carbon dioxide , steam , and nitrogen . Gaseous volumes computed by the ideal gas law tend to be too large at high pressures characteristic of explosions. Ultimate volume expansion may be estimated at three orders of magnitude, or one liter per gram of explosive. Explosives with an oxygen deficit will generate soot or gases like carbon monoxide and hydrogen , which may react with surrounding materials such as atmospheric oxygen . Attempts to obtain more precise volume estimates must consider
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#17327911934464628-445: The explosive material is propagated by a flame front which moves relatively slowly through the explosive material, i.e. at speeds less than the speed of sound within the substance (which is usually still higher than 340 m/s or 1,220 km/h in most liquid or solid materials) in contrast to detonation, which occurs at speeds greater than the speed of sound. Deflagration is a characteristic of low explosive material. This term
4717-651: The explosive material, but a practical explosive will often include small percentages of other substances. For example, dynamite is a mixture of highly sensitive nitroglycerin with sawdust , powdered silica , or most commonly diatomaceous earth , which act as stabilizers. Plastics and polymers may be added to bind powders of explosive compounds; waxes may be incorporated to make them safer to handle; aluminium powder may be introduced to increase total energy and blast effects. Explosive compounds are also often "alloyed": HMX or RDX powders may be mixed (typically by melt-casting) with TNT to form Octol or Cyclotol . An oxidizer
4806-442: The explosive may become more sensitive. Increased load density also permits the use of more explosive, thereby increasing the power of the warhead . It is possible to compress an explosive beyond a point of sensitivity, known also as dead-pressing , in which the material is no longer capable of being reliably initiated, if at all. Volatility is the readiness with which a substance vaporizes . Excessive volatility often results in
4895-414: The explosive properties of two or more compounds; it is important to examine the data from several such tests (sand crush, trauzl , and so forth) in order to gauge relative brisance. True values for comparison require field experiments. Density of loading refers to the mass of an explosive per unit volume. Several methods of loading are available, including pellet loading, cast loading, and press loading,
4984-409: The explosive. Hygroscopicity is a measure of a material's moisture-absorbing tendencies. Moisture affects explosives adversely by acting as an inert material that absorbs heat when vaporized, and by acting as a solvent medium that can cause undesired chemical reactions. Sensitivity, strength, and velocity of detonation are reduced by inert materials that reduce the continuity of the explosive mass. When
5073-429: The explosives on the market today are sensitive to an n. 8 detonator, where the charge corresponds to 2 grams of mercury fulminate . The velocity with which the reaction process propagates in the mass of the explosive. Most commercial mining explosives have detonation velocities ranging from 1,800 m/s to 8,000 m/s. Today, velocity of detonation can be measured with accuracy. Together with density it
5162-489: The field. Glassine envelopes carry pharmacy reformulated drugs and illicit drugs such as cocaine and heroin . Photographers used glassine sleeves for many decades to safely store their processed films. Glassine is also used to pack firecrackers , as it is moisture resistant. It is used for its transparent qualities to fold origami tessellations . Glassine is an outer covering on paperboard tubes, particularly those used in model rocketry , for water protection. In
5251-592: The firecracker was a type of heated bamboo , used as early as 200 BCE, that exploded when heated continuously. The Chinese name for firecrackers, baozhu ( 爆竹 ), literally means "exploding bamboo." After the invention of gunpowder, gunpowder firecrackers had a shape that resembled bamboo and produced a similar sound, so the name "exploding bamboo" was retained. In traditional Chinese culture, firecrackers were used to scare off enemies or evil spirits. Firecrackers are generally made of cardboard or plastic, with flash powder , cordite , smokeless powder , or black powder as
5340-569: The first three days of the traditional New Year, it is a tradition that people compete with each other by playing with firecrackers. However, many urban areas banned them in the 1990s. For example, they were banned in Beijing 's urban districts from 1993 to 2005. Since the ban was lifted, the firecracker barrage has been tremendous. An unusual feature is that many residents in major cities look down on street-level fireworks from their tower blocks. Bans are rare in rural areas. Firecrackers are legal in
5429-413: The first time in warfare. The Chinese would incorporate explosives fired from bamboo or bronze tubes known as bamboo firecrackers. The Chinese also inserted live rats inside the bamboo firecrackers; when fired toward the enemy, the flaming rats created great psychological ramifications—scaring enemy soldiers away and causing cavalry units to go wild. The first useful explosive stronger than black powder
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#17327911934465518-587: The flash-light cracker's heyday from the 1920s through the early 1970s. Only a small percentage of brands lasted more than a year or two. Collectors now seek the various labels from the era. Until the mid-1980s, firecracker production was low-tech. They were handmade, beginning with rolling tubes. Once the firecracker tubes were rolled by hand (commonly from newspaper) and labelled, and then filled with powder, their ends were crimped and fuses inserted, all by hand. These finished firecrackers were usually braided into "strings" and sold in packs which came in many sizes, from
5607-532: The history of chemical explosives lies in the history of gunpowder . During the Tang dynasty in the 9th century, Taoist Chinese alchemists were eagerly trying to find the elixir of immortality. In the process, they stumbled upon the explosive invention of black powder made from coal, saltpeter, and sulfur in 1044. Gunpowder was the first form of chemical explosives and by 1161, the Chinese were using explosives for
5696-539: The largest outside China, is accompanied by numerous firecrackers, both officially sanctioned and illicit. In 1994, the Government of Vietnam decided to ban firecrackers nationwide. Only fireworks displays produced and performed by the government are permitted. 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
5785-450: The manufacturing operations. A primary explosive is an explosive that is extremely sensitive to stimuli such as impact , friction , heat , static electricity , or electromagnetic radiation . Some primary explosives are also known as contact explosives . A relatively small amount of energy is required for initiation . As a very general rule, primary explosives are considered to be those compounds that are more sensitive than PETN . As
5874-436: The moisture content evaporates during detonation, cooling occurs, which reduces the temperature of reaction. Stability is also affected by the presence of moisture since moisture promotes decomposition of the explosive and, in addition, causes corrosion of the explosive's metal container. Explosives considerably differ from one another as to their behavior in the presence of water. Gelatin dynamites containing nitroglycerine have
5963-443: The molecule is said to have a zero oxygen balance. The molecule is said to have a positive oxygen balance if it contains more oxygen than is needed and a negative oxygen balance if it contains less oxygen than is needed. The sensitivity, strength , and brisance of an explosive are all somewhat dependent upon oxygen balance and tend to approach their maxima as oxygen balance approaches zero. A chemical explosive may consist of either
6052-457: The more important characteristics are listed below: Sensitivity refers to the ease with which an explosive can be ignited or detonated, i.e., the amount and intensity of shock , friction , or heat that is required. When the term sensitivity is used, care must be taken to clarify what kind of sensitivity is under discussion. The relative sensitivity of a given explosive to impact may vary greatly from its sensitivity to friction or heat. Some of
6141-570: The most popular. The final operation involved applying a branded label on each pack, then bundling finished packs into wholesale lots called "bricks" which contained an average of 80 packs each (varying according to the size of the packs being bundled; for example, packs of 32 crackers might have 40 packs per brick, compared to packs of 16 or 20 with 80 packs per brick). Firecrackers, as well as other types of explosives, are subject to various laws in many countries, although firecrackers themselves are not usually considered illegal contraband material. It
6230-433: The painted surface. Therefore, art conservators do not recommend that it be used to wrap paintings. Philatelists use glassine envelopes to store stamps, and stamp hinges are made of glassine. Amateur insect collectors use glassine envelopes to store specimens temporarily in the field before they are mounted in a collection. Entomologists collecting for research may likewise use such envelopes to store whole specimens in
6319-549: The police carries out the "Peace and good" action with the aim of prevention of people from getting hurt and violating public order. The penalties for unauthorized use of pyrotechnic articles range between 1,000 and 15,000 kunas ( € 135 - €2,035) for people, and between 10,000 and 80,000 kunas (€1,355 - €10,850) for companies. For a legal guardian of a child under the age of 14 who have used pyrotechnic articles, fine ranges between 1,000 and 3,000 kunas (€135 - €405). As of 2008, most urban areas in mainland China permit firecrackers. In
6408-410: The possibility of such side reactions, condensation of steam, and aqueous solubility of gases like carbon dioxide. Oxygen balance is an expression that is used to indicate the degree to which an explosive can be oxidized. If an explosive molecule contains just enough oxygen to convert all of its carbon to carbon dioxide, all of its hydrogen to water, and all of its metal to metal oxide with no excess,
6497-426: The production of light , heat , sound , and pressure . An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances. The potential energy stored in an explosive material may, for example, be: Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of
6586-570: The production of dust; their emissions are 30% lower but are also of reduced loudness, at 110-125 decibels instead of the more than 160 decibels of traditional firecrackers. However, green crackers still contain harmful pollutants such as aluminium, barium, potassium nitrate and carbon. Early (pre-1920s) Chinese firecrackers (also known as "Mandarin firecrackers") were typically 1 ⁄ 2 to 2 inches (13 to 51 mm) long, and approximately 1 ⁄ 4 inch (6.4 mm) in diameter, and were charged with black powder . Mandarin crackers produced
6675-477: The propellant. This is not always the case, however. Anything from match heads to kerosene and lighter fluid has been used successfully in making firecrackers.The key to loud firecrackers, however, although in part lying in the propellant substance, is pressure. The entire firecracker must be very tightly packed in order for it to work best. Flash powder, however, does not need to be packed tightly, and should not be. James Dyer Ball , in his book Things Chinese, has
6764-452: The sale or use of firecrackers, or banning the use of firecrackers in the street, primarily because of safety or environmental reasons. These rules also require a permit from the local government, as well as any relevant local bodies such as maritime or aviation authorities (as relevant to the types of firecrackers being used) and hospitals, schools, etc., within a certain range. In most states and territories, firecrackers are illegal without
6853-674: The sale, distribution, manufacture and use of firecrackers for public safety . Under Republic Act 7183, there are certain firecrackers that are legal such as Judas' belt and the prohibition of a certain firecracker and pyrotechnic devices shall be determined by the Director-General of the Philippine National Police . Although, there are cities in the Philippines banning all kinds of firecrackers and those cities are Muntinlupa (since 2013), Olongapo (since 2008) and Davao City (since 2001). Injuries involving
6942-535: The strictest in the world, equal to Chile's. Private citizens are banned from using fireworks in the Minor Offences Act 1955 and Explosives Act 1957. However, the illegal setting of fireworks and firecrackers are rarely enforced as they are tolerated during festive seasons. In addition, fireworks are readily available in the community. The government only allows fireworks for public events, and some authorised events held by businesses and other groups with
7031-492: The sum of the masses of the two initial layers. There are applications where a shock wave, and electrostatics, can result in high velocity projectiles such as in an electrostatic particle accelerator . An explosion is a type of spontaneous chemical reaction that, once initiated, is driven by both a large exothermic change (great release of heat) and a large positive entropy change (great quantities of gases are released) in going from reactants to products, thereby constituting
7120-499: The test methods used to determine sensitivity relate to: Specific explosives (usually but not always highly sensitive on one or more of the three above axes) may be idiosyncratically sensitive to such factors as pressure drop, acceleration, the presence of sharp edges or rough surfaces, incompatible materials, or even — in rare cases — nuclear or electromagnetic radiation. These factors present special hazards that may rule out any practical utility. Sensitivity
7209-553: The time, noise level and type (mandatory use of less polluting firecrackers) that can be used. Nonetheless, many firecrackers were used to celebrate the Vijayadashami and Diwali holidays in 2020, immediately after which Delhi's air pollution was over 9 times the level that the World Health Organization considers safe. Aaratrika Bhaumik writing for the website "livelaw.in" mentions the ban put in place by
7298-425: The two layers. As the length of time the shock wave spends at any point is small, we can see mixing of the two metals and their surface chemistries, through some fraction of the depth, and they tend to be mixed in some way. It is possible that some fraction of the surface material from either layer eventually gets ejected when the end of material is reached. Hence, the mass of the now "welded" bilayer, may be less than
7387-500: The two. However, there are some exceptions. The usage of firecrackers is legal in some metropolitan areas such as Jakarta and Medan , where the degree of racial and cultural tolerance is higher. Fireworks and firecrackers are not permitted in the Republic of Ireland; however, many people smuggle them from Northern Ireland , where they are legal. They are most common around Halloween . Irish anti-firecracker laws are considered among
7476-689: The use or ingestion of " Piccolo " sticks account for the majority of firecracker-related incidents in the country. However, in December 2020, firecrackers were banned in some areas of Metro Manila to prevent injuries and avoid mass gatherings in the region due to the COVID-19 pandemic . For example, Mayor Joy Belmonte of Quezon City said that fireworks and firecracker use is strictly prohibited in basketball courts, streets and public spaces, and can only be used in designated firecracker zones. Some provinces and municipalities outside of Metro Manila also imposed
7565-529: The very small ("penny packs" containing as few as four to six firecrackers) to the most common size packs (containing 16 and 20 crackers per pack), to larger packs (containing 24, 30, 32, 40, 50, 60, 72, 90, 100, and 120 firecrackers), to huge "belts" and "rolls" (packages containing strings of several hundred to several thousand crackers—Phantom Fireworks sells rolls as large as 16,000 firecrackers). Firecracker packages were wrapped in colourful and translucent glassine paper, as well as clear cellophane, with glassine
7654-535: The year). Other fireworks have no such restrictions, however, they are not recommended for children below 12 years and guidance by adults is advised. Certain fireworks are available only to professionals. Firecrackers sold to consumers are restricted to 0.95 grams of black powder. The ban on larger firecrackers went into effect in 1996. Before, mid-size kiinanpommi or kiinari ("Chinese bomb") and tykinlaukaus and large tykäri ("artillery shot") had become cheap and common products that were often used by children after
7743-799: Was nitroglycerin , developed in 1847. Since nitroglycerin is a liquid and highly unstable, it was replaced by nitrocellulose , trinitrotoluene ( TNT ) in 1863, smokeless powder , dynamite in 1867 and gelignite (the latter two being sophisticated stabilized preparations of nitroglycerin rather than chemical alternatives, both invented by Alfred Nobel ). World War I saw the adoption of TNT in artillery shells. World War II saw extensive use of new explosives (see: List of explosives used during World War II ) . In turn, these have largely been replaced by more powerful explosives such as C-4 and PETN . However, C-4 and PETN react with metal and catch fire easily, yet unlike TNT, C-4 and PETN are waterproof and malleable. The largest commercial application of explosives
7832-406: Was cut into strips of 14 inches (360 mm) long and 1 ⁄ 3 inch (8.5 mm) wide, laid on a table; a string of gunpowder was placed at the center with a hollow tube, then twisted up to make a piece of fuse. The firecracker tubes were made from pieces of straw paper wrapped around iron rods of various diameters and then tightened with a special tool. 200 to 300 firecrackers were tied up in
7921-639: Was established in Calcutta during the 19th century. In October and November, farmers from Punjab and Haryana burn agricultural waste and the weather tends not to be windy, so Delhi's air pollution usually increases, which has been a major environmental problem in recent years. Firecrackers for the Diwali holiday can worsen this pollution. In October 2017, the Supreme Court banned firecrackers in Delhi, as
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