SCICAN INVESTIGATION REPORT

Purpose:

To learn about the different areas of explosives and the separate

explosives related to each group.

Explosive adj. 1. of, involving, or characterized by an explosion

or explosions.

2. capable of exploding or tending to explode.

3. potentially violent or hazardous; dangerous: an explosive situation.

4. Phonetics. another word for plosive.

5. a substance that decomposes rapidly under certain conditions with the

production of gases, which expand by the heat of the reaction. The energy

released is used in firearms, blasting, and rocket propulsion.

The context of explosive that I am dealing with in my investigation is

the fifth context mentioned above. I chose to do explosives because I am

very interested in them and their abilities.

Basic Description of Explosives

Explosives are substances that produces a rapid, violent reaction when

exposed to heat, a strong blow or a special detonator. During the

reaction, explosives give off large amounts of gases at high pressure. The

powerful blast of energy released during an explosion gives explosives many

commercial and military uses. Explosives let construction workers clear

land away for building roads or buildings with little effort. They are

used in digging mines and to loosen the flow of oil deep beneath rock in

oil wells. They blow away tunnels through mountains and send rockets into

space. In war, explosives are used to damage cities, destroy ships and

airplanes, and kill enemy troops. As you see, explosives aren't always

used as harmless substances.

Explosives may be solids, liquids, or gases. However, all explosives

consist of a fuel and an oxidizer--a substance that supplies the oxygen

needed to make the fuel burn. When the most powerful explosives detonate,

a chemical reaction takes place very quickly (usually in less than a

millionth of a second). Liquids and solids change to hot gases that expand

with a large blast of heat and pressure. The higher the pressure, the more

powerful the explosion is.

There are four main types of chemical explosives--primary explosives,

high explosives, blasting agents, and low explosives.

Primary Explosives should be handled in small quantities. They are

very sensitive to heat, and even a spark of static electricity can cause

them to explode. A few primary explosives include lead azide, lead

styphnate, and mercury fulminate. They are usually used in detonators to

set off other explosives.

High Explosives detonate with greater power than primary explosives but

are less sensitive. They usually require a detonator to set them off.

Common types of high explosives include nitroglycerin; RDX; TNT; PETN; and

pentolite, a combination of TNT and PETN. Most high explosives are used

commercially for blasting and excavating, but they also are used by the

military in grenades, bombs, and artillery shells. High explosives can be

mixed with substances called plasticizers to produce plastic explosives.

Plasticizers, like such as oil and wax, make it easy to shape explosives

into various forms. Plastic explosives have been used mostly by terrorists

because of the ease of concealment but it has been used in bombs and by the

armed forces in land mines.

Blasting Agents are the safest and least expensive explosives used in

industry. They are usually used to blast away rock in excavating and

mining operations. Common blasting agents include dynamite and mixtures of

ammonium nitrate and fuel oil.

Low Explosives burn rapidly rather than detonate. The most common type

of low explosive is gunpowder. It serves as a propellant to shoot

ammunition from guns and other weapons. Fireworks are also low explosives.

Below, I will talk about high explosives, low explosives, and blasting

agents. I will talk about the explosives in each group separately.

High Explosives

Nitroglycerin

Nitroglycerin, also called Nitroglycerol, is a powerful explosive. It

is the principal explosive ingredient of dynamite. Pure nitroglycerin is a

heavy liquid that is clear and has the consistency of motor oil. The

commercial product is usually a yellowish or brownish colour. When

nitroglycerin explodes, it expands to form gases that take up more than

1,000 times as much space as the liquid. That would mean that if you had

10 ml of nitroglycerin, the gases created from the explosion would be close

to 10,000 ml. The explosion of nitroglycerin is about three times as

powerful as that of an equal amount of gunpowder, and the explosion speed

is 25 times as fast as that of gunpowder. Although its explosive

capabilities are very great, it is not often used as an explosive. Doctors

use nitroglycerin to treat certain heart and blood-circulation diseases.

RDX (Cyclonite or Hexogen)

RDX is a powerful explosive also known as cyclonite and hexogen. It is

commonly used as a war explosive, being the main explosive charge in bombs.

It has wide use in detonators and fuses. RDX is made by the action of

nitric acid on hexamethylene-tetramine, a product of formaldehyde and

ammonia. When RDX is mixed with liquid TNT, an explosive called

Composition B is formed. This explosive is more powerful than TNT, and has

replaced it in most artillery shells.

TNT (Trinitrotoluene)

TNT is short for trinitrotoluene, a powerful solid explosive. TNT is

made up of the elements nitrogen, hydrogen, carbon, and oxygen. The

explosive is made by nitrating the chemical compound toluene. The

explosive made forms in pale yellow crystals that may darken to a darker

brown colour. These crystals of TNT can be handled safely. TNT can be

melted at low heat without igniting, and so can be molded to increase its

usefulness. TNT is used alone and in mixtures with other explosives, such

as PETN, RDX, and ammonium nitrate. It is mainly used as the explosive

charge for shells and bombs.

PETN (Pentaerythritol Tetranitrate)

PETN is short for pentaerythritol tetranitrate, an explosive more

powerful than TNT. It is used as the core of detonating caps and fuses

because it is capable of exploding in small devices. The combination of

PETN and TNT is called pentolite. Doctors also use PETN like they do

nitroglycerin, in treating some heart disorders.

Low Explosives

Gunpowder

Gunpowder is an explosive material that burns rapidly to form

high-pressure gas. Expansion of this gas inside the barrel of a gun can

accelerate a bullet to great speed. Gunpowder is therefore used as a

propellant in a variety of ammunition. It is also used in explosives for

blasting operations, in fireworks, and in fuses.

There are several kinds of gunpowder. The first important substance

used as gunpowder in guns and cannons was black powder. Black powder

consists of a mixture of saltpeter (potassium nitrate), charcoal, and

sulfur. These ingredients can be mixed together in the right proportions

and be used as a powder. Sometimes, graphite is added. The texture of

black powder can range from fine powder to larger pellets.

The basic formula for black powder has been modified for special

purposes. Sulfurless gunpowder contains saltpeter and charcoal but no

sulfur. It is not as powerful as regular black powder, but it corrodes the

gun barrel less. Another variation is the black powder used in fireworks

and blasting agents. The saltpeter is sometimes replaced by less expensive

sodium nitrate.

Cordite

Cordite was one of the original smokeless powders used to propel

projectiles from guns. It replaced gunpowder in many cases because it

burned with a lot less smoke. However, cordite damaged gun barrels much

more than gunpowder did. The name cordite refers to the cordlike lengths

in which it was made. Cordite is composed of 30 percent nitroglycerin, 65

percent nitrocellulose, and 5 percent petrolatum.

Blasting Agents

Dynamite

Dynamite is one of the most important industrial explosives. It is

used to blast out damsites, canal beds, mines, quarries, and the

foundations for large buildings. It also has been used for demolition in

warfare.

The main explosive in dynamite is nitroglycerin. It is mixed with

other materials--some explosive and some nonexplosive--and packed in

cylinders made of waxed paper or plastics. These cylinders, called

cartridges, range from 7/8 to 8 inches (22 to 200 mm) in diameter and from

4 to 30 inches (10 to 76 cm) in length.

To use dynamite, workers insert an explosive device called a detonating

cap or blasting cap into one end of the cartridge. They place the

cartridge in a hole bored into the material to be blasted. Earth is packed

around and behind the cartridge. After moving to safety, the workers set

off the detonating cap--and the explosion--by means of a fuse or an

electric current.

There are four main types of dynamite. They are: straight dynamite,

ammonia dynamite, straight gelatin, and ammonia gelatin.

Straight dynamite contains nitroglycerin and an absorbent, chemically

reactive mixture, such as wood pulp and sodium nitrate. It is the oldest

type and has been replaced by ammonia dynamite for most uses.

Ammonia dynamite is more powerful, safer, and less expensive than

straight dynamite. It contains ammonium nitrate and produces fewer toxic

fumes and cooler gases than other dynamites do. It is called a permissible

explosive, which means that it can be used safely in mines where extreme

heat could ignite dust or gas in the air.

Straight gelatin is made from a stiff gel called blasting gelatin.

Blasting gelatin consists of nitroglycerin mixed with a small amount of

nitrocellulose. Sodium nitrate and other ingredients are added to make

straight gelatin. Straight gelatin has been replaced by ammonia gelatin

for most uses. Ammonia gelatin is made by adding ammonium nitrate and

other ingredients to blasting gelatin. Ammonia gelatin is waterproof. It

is used for underwater blasting.

Conclusion: I have learned many new things that I did not know about

explosives before I did my investigation. I learned that there are four

main groups of explosives, and each group has different uses.