Showing posts from June, 2022

Process of Dyeing Fabric

To dye fiber with a dye, some certain steps are to be followed only then dye molecules will get fixed on the fiber and we will get our desired colored fiber. So, the following are some steps that are to be followed during the dyeing process: 1. Sourcing and Bleaching In this type, fiber is collected from the source and any loose, hairy or gummy materials are removed from the fiber. Then, impurities or any natural color of the fiber are removed through bleaching. 2. Preparation of Dye bath In this step, a dye bath is prepared in which the whole process of dyeing a textile fiber takes place. A dye bath contains dye and water which is generally heated to get a proper mixture. 3. Coloration In this step, textile fiber is colored through dyeing. The color should not readily be removed by rinsing in water or by normal washing procedures. Also, the color should not fade by exposure to light. Following are the phenomenon involved at the molecular level during the coloration of textile mater

History and Development of Forensic Science

The term 'forensic' is obtained from the Latin word 'Forensis' which means "court of justice" . So we can say, forensic science is a branch of science that deals with the individualization, recognition, identification, and evaluation of physical evidence by the use of natural science for criminal justice. Forensic science is also known as 'criminalistics' in some countries with branches like fingerprints, documents, ballistics, odontology, etc. It is derived from major branches of science like physics, biology, and chemistry. In the 19th century when natural science began to develop rapidly, forensic science started deepening its roots in criminal justice. Forensic science was widely accepted because there is no place for the torture of criminals for detecting crime in a civilized society.  Forensic science was made more famous by sir Arthur Conan Doyle's fictional character 'sherlock homes' in which crime investigation is done by scie

Documentation of the Crime Scene: Step by Step

What is documentation of the crime scene and Why it is done? After securing the crime scene, the next most important step is documentation of the crime scene because documentation permanently records the crime scene and its physical evidence. Documentation should be done without any wastage of time as the scene and its evidence may get altered over time. The documentation should be done innovatively and the originality of the crime scene should be maintained and documentation should not have pauses or breaks, it should remain constant till the whole crime scene is documented. There are four main tasks of documentation that is note-making, photography, videography , and sketching . It should be noted that all four tasks are necessary and none is a substitute for another. For example, notes are not substitutes for photography, video is not a substitute for sketching, etc. Following are the sequence for crime scene documentation: 1. Note making Documentation of crime scene in the f

Phenolphthalein: Preparation, Properties and Applications

What is Phenolphthalein? Phenolphthalein is an organic compound having the chemical formula C₂₀H₁₄O₄ that is used as a ㏗ indicator in acid-base titrations. So, as an indicator, it turns pink to red in alkaline and is colorless in acid solutions. In short, it can be written as 'HIn' or '㏗㏗'. Preparation of Phenolphthalein Phenolphthalein can be synthesized by condensation of phthalic anhydride with two equivalents of phenol under acidic conditions. Properties of Phenolphthalein Phenolphthalein is white-yellow, in its crystalline form. It is readily soluble in alcohols and mildly soluble in water. It does not have taste or smell and it is carcinogenic. It appears colorless till pH 8.5 and above that it appears as pink to deep red. Applications of Phenolphthalein It is commonly used as an indicator in acid-base titrations. It turns colorless in acidic solutions and pink in basic solutions. It may be used as a laxative but it is not advisable due to the suspected car