Sciencedoze: Science, Education and Technology

1. Classification based on size and handling mechanism 1. Handguns Firearms that are short and compact and can be held in one hand. They have generally short barrels. They are further classified into two types: (a) Revolver A revolver is a short barrel firearm having a cylinder at the rear of the barrel. This cylinder has various chambers in which the cartridge is placed. When the trigger is pulled, the hammer facing one of the chambers of the cylinder strikes the primer of the cartridge, and hence the bullet fires. (b) Pistol A pistol is also a short barrel firearm having a magazine loaded with bullets. The magazine has a spring beneath it which push the new cartridge into the firing chamber after the previous bullet is fired and the process keeps going on till the magazine got empty. Pistols are available in all calibers ranging from 5 to 12 mm. 2. Shoulder Gun Firearms that are long barrels and relatively bigger and fired only with the assistance of a shoulder are known as should

What is Methyl Orange? Methyl orange is a weak acid that breaks down into orange neutral molecules when it comes into contact with water. Methyl orange shows red color in the acidic medium and yellow color in the basic medium. That's why it is used as a pH indicator in titration due to its clear and distinct color variance properties at different pH. Preparation of methyl orange Methyl orange is prepared from sulphanilic acid N, N-dimethylaniline through a diazonium coupling reaction. The first product from the coupling is the bright red form of methyl orange, called helianthin. In the base, helianthin is converted to the orange sodium salt, called methyl orange. Mechanism of preparation of methyl orange The mechanism of this reaction is given below: Step 1:  Sulphanilic acid reacts with sodium carbonate extract and gets converted into sodium salt of p-amino benzene sulphonate Step 2: It undergoes a diazotization reaction in presence of nitrous acid to form diazonium chloride

Following are the phases of digital forensics: (i) Collection of information/ Pre search consideration Before reaching the scene of the crime, the expert should have preliminary knowledge about the nature of the cybercrime. This information can be obtained from the first responding officer. Pre-search consideration helps the investigator to physically and mentally prepare for the crime and helps him to carry relevant tools to the scene of the crime.  Following are the three steps involved in pre-search consideration: (a) Securing and Evaluating In this stage, the expert asks questions regarding crime and pays special attention to the safety issues. He also checks the consent issues. (b) Conducting preliminary interviews Take the preliminary interview of the owner or user of the computer system found at the scene of the crime. If the system is password protected then an expert may ask the access to the system. Also, try to know the purpose of the use of a computer by the user. (c) Docum

What is Digital Forensics? The branch of forensic science that deals with the identification, collection, preservation, analysis, and reporting of any valuable digital evidence found at the scene of the crime is called digital forensics. It is also based on Locard's principle of exchange which states that "when a person comes into contact with an object, a mutual transfer of pieces of evidence takes place".  Here, digital forensic evidence like temporary files, commands, history, deleted data, etc can be found in the computer. Digital forensics helps the court of law in the conviction of criminals by studying digital evidence and maintaining a proper chain of custody. Branches of Digital Forensics Following are the branches of digital forensics: (i) Mobile forensics Mobile forensics is the branch of digital forensics that deals with the identification, collection, preservation, analysis, and reporting of any mobile device like a smartphone, tablet, etc found at the s

What is Death? Death is the irreversible cessation of all biological functions that helps to sustain an organism. The remains of a dead organism normally begin to decompose shortly after death. Death is an inevitable, a universal process that eventually occurs in all living organisms. Types of Death There are mainly two types of death 1. Somatic Death It is also known as clinical death . It refers to the complete and irreversible cessation of the function of the brain followed by the cessation of the function of the heart and lungs. 2. Molecular death It is also known as cell death. It refers to the complete and irreversible cessation of individual tissues of the cells. It takes place after the somatic death and in this type of death individual cells and other biomolecules in the system die.  This happens due to the loss of blood flow and oxygen for the survival of cells and tissues. Causes of death 1. Asphyxia The death of an individual due to interference with the intake of oxygen is

What are Mechanical Injuries? Injuries that are produced by any kind of mechanical force like blunt, sharp objects, firearms, etc are known as mechanical injuries. Injuries are defined as any harm to any person in body, mind, reputation, or property. Types of mechanical Injuries (A) Blunt force mechanical injuries Injuries caused by blunt force impact by objects like bat pipe, rod, etc are known as blunt force mechanical injuries. The injuries by blunt force produce abrasion, bruise, laceration, etc. 1. Abrasion Injury caused by the removal of the superficial epithelial layer of skin (generally epidermis) by friction against the rough surface is called abrasion. Following are the types of abrasion: (a) Scratch/ Linear Abrasion Linear abrasion is caused by a sharp or pointed object like a fingernail, thorn, or pin on the surface of the skin. It has some length but no significant width. (b) Graze abrasion (sliding/scrape/grinding abrasion) Graze abrasion is caused by horizontal or ta

What are explosives? An explosive is a chemical substance that tends to release a great amount of potential energy that can produce an explosion if released suddenly. It is accompanied by the production of light, heat, sound, and pressure. The explosives can be classified based on their chemical composition, velocity of detonation, sensitivity towards heat and light, and physical forms. But broadly explosives are of three types: low explosives , high explosives , and miscellaneous . The latter is subdivided into IEDs and nuclear explosives. Classification of explosives 1. Low explosives Low explosives are chemical compounds in which the rate of decomposition through the material is less than the speed of sound. The deflagration rate in low explosives is less than 4000 m/sec. The proportion of burning of explosives depends on combustion gas, pressure, grain size, form, and composition. Examples of low explosives are gunpowder, flash powder, pyrotechnics, smokeless powder, etc. (a) Gu

Based on origin Based on their origin, drugs of abuse can be classified into the following three categories: 1. Natural Drugs Drugs that are obtained from plants and require little or no processing at all are known as natural drugs. Eg: Cannabis, opium, coca paste, etc. 2. Semi-synthetic Drugs Drugs that are obtained from plants but undergo the same chemical process are known as semi-synthetic drugs. Eg: Heroin, Cocaine, etc . 3. Synthetic Drugs Drugs that are synthesized absolutely through a chemical process are known as synthetic drugs. Eg: Amhetamine, diazepam, etc. Based on their use Based on the purpose of their use, different drugs can be classified into the following categories: 1. Therapeutic Drugs Drugs that have a certain therapeutic effect in terms of healing and prevention of certain diseases are known as therapeutic drugs. They are further classified into four categories: (i) Analgesics and Antipyretics Drugs that are used to relieve or decrease pain without the loss of

The history of firearms started in the 9th century when the Chinese accidentally developed gunpowder. After this, the gunpowder spread to the whole world from the middle east to Europe and Africa. So, here is the development of firearms since the 13th century. 1. Hand Canon (1271-1368) It was first used by the Chinese Yuan dynasty in 1300. These hand canons were made of bamboo and the projectile along with gunpowder was loaded through the muzzle end. Also, a small hole is placed at the breech end which is ignited that causes an explosion realizing the projectile from the canon. Hand cannons required much strength to hold for better stability. 2. Match lock (The early 1400s) In the matchlock firing mechanism, a wick was placed near the propellent/primer through the breech end of the weapon, and when that wick is ignited it causes a spark in the propellent which burns rapidly and pushes the projectile into a forward direction. The main disadvantage of this system is that it can'

What is glass transition temperature? When plastic or rubber is cooled up to a certain temperature, it becomes so hard and brittle that it breaks into pieces on the application of stress. So, the temperature below which the polymer becomes hard, brittle, and glassy and above which it is softener and flexible is known as glass transition temperature (Tɡ). The glass transition is a property of only the amorphous region of a semi-crystalline solid whereas the crystalline portion remains crystalline during the glass transition. It is important to note that the transition does not occur suddenly at a unique temperature but rather over a range of temperatures. The temperature in the middle of the inclined region is taken as the Tɡ. Significance of glass transition temperature (Tg) Glass transition temperature (Tɡ) is used as a measure for evaluating the flexibility of a polymer and the type of response the polymeric material would exhibit to mechanical stress. Glass transition temperature (

What is Raman Spectroscopy? Raman spectroscopy was given by an Indian Physicist Sir C.V Raman , which is based on inelastic scattering of monochromatic light with the sample. The resulting light will have a different frequency than incident light due to this inelastic scattering.  This technique is widely used to analyze vibrational, rotational, and other low-frequency interactions in the molecule. This significantly helps in the elucidation of molecular structure, identifying functional groups, etc. Principle of Raman Spectroscopy Raman spectroscopy is based on the inelastic scattering of electromagnetic radiation with the molecule. We have two types of scattering that are elastic and inelastic scattering.  Elastic scattering obeys the Rayleigh law that states that there will be no loss of energy and momentum of the incidence radiation and scattered radiation. That's why this scattering is also known as Rayleigh scattering. Whereas, there will be some conditions (1 in million