This is short for coronary thrombosis, which is the medical term for heart attack, and it occurs when a branch of a coronary artery gets blocked, which stops oxygenated blood reaching the heart muscles, so affecting the operation of the heart.

A cogwheel train is a train fitted with one or more cogwheels, which mesh with the toothed rail-rack, running usually between the normal rails. The system, operating on rack and pinion arrangement, is used in regions where trains operate on steep heights within a short span of time. Most cogwheel railways are mountain railways, although a few are transit railways …

A chromophore is a group of atoms and electrons (or moiety) i.e. part of organic molecules responsible for its colour. It is an extended delocalised systems of electrons in a compound which gives its colour e.g. chlorophyll’s porphin ring, or an azo dyes benzene ring linked to N=N double bond. When a molecule absorbs certain wavelengths of visible light and …

A chemical bond is one in which atoms of different or same elements combine to become stable. There are two types of chemical bonds – electro-valent bond and co-valent bond. In an electro-valent bond, a metal donates an electron to a non-metal and forms the bond. Such bonds are very strong. A co-valent bond is formed between non-metals only. These …

A catalyst is any substance which causes a chemical reaction without itself undergoing any chemical change. Many industrial processes depend on this property. A simple example is when oxygen and hydrogen combine together quickly in the presence of platinum. Platinum is therefore, the catalyst. It is believed that this is due to the gases being absorbed on the surface of …

An unforeseen chain of events due to an act affecting a system, much like how a waterfall cascades down, is called cascade effect. Cascade effects are commonly visualised in tree structures called event trees.

Cantenna stands for Can + Antenna. To increase the range of communication, an amateur radio enthusiast attempted to use a tin can of potato chips as a directional element in addition to a basic yagi antenna operating at 2.4 GHz frequency. This helped in directing more transmit power towards the receiver, thereby improving the communication range. As this method was …

A cameo is an engraved gem on which the subject or figure is carved in relief on a stone or other material which provides two layers of color, such as chalcedony, onyx and shell. One color forms the background while the design is cut out of the other. Finished cameos are often mounted as brooches. Favourite subjects are portraits and …

A Bunsen burner is a gas burner consisting of a tube with a small gas jet at the lower end and adjustable air inlet by means of which the heat of the flame can be controlled. It is used in laboratories and produces a hot non-luminous flame it the air and gas mixture is about three parts air to one …

A buckyball or fullerene is a very newly found allotrope of carbon. Buckyball is a carbon molecule structure (C60) shaped like a hollow sphere. Also called fullerene (buckminsterfullerene), it is composed of carbon atoms. Spherical fullerenes are called buckyballs whereas cylindrical ones are called buckytubes. Harold Kroto, Richard Smalley, James Heath and Robert Curl discovered (C60) at Rice University. It …