Look in any jeweller’s window, and you are bound to see diamonds, the white, glittering gems which are so valuable and so beautiful to look at. It’s hard to think that the diamonds which sparkle in the shop windows came out of the ground as lumps of dull rock, isn’t it? But this is how they are found. Diamonds are …
Read More »What is a dhow?
The word ‘dhow’ is used to describe any kind of Arab sailing vessel. They are the regular Arab trading craft, and make along voyages from the Red sea and Persian Gulf down to the African coast. The commonest are the small, square-sterned dhows known as ‘sambuks’. Then there are the smart ‘booms’, and the short, wide ‘bedeni’ from Muscat in …
Read More »What is a detergent?
A detergent is a substance, which has the power to cleanse. This description applies to soap, as well as to soap less shampoos and washing powders. A detergent must have surface activating properties, which means it must be able to tc break down the surface tension of water. In the process of cleaning the detergent acts as a bridge between …
Read More »What is a depression?
Cold air flows outwards from the poles, while warm subtropical air moves polewards. The cold and warm air meet along a line called the polar front. Because of the great difference in temperature, the cold and warm air do not mix. Instead, warm air flows into bends in the polar front and cold air flows in behind it. This sets …
Read More »What is a datum line in geography?
A datum (plural datums or data) is a reference point from which measurements are made. In surveying and geodesy, a datum is a set of reference points on the Earth’s surface against which position measurements are made. Horizontal datums are used for describing a point on the Earth’s surface in latitude and longitude or another coordinate system. Vertical datums measure …
Read More »What is a cyclone?
Very simply, a cyclone is a kind of storm, and a storm is air which is moving quickly from one place to another. A storm begins when a mass of warm, moist air from the equator meets a mass of cold, dry air from the northern hemisphere. The two masses of air will not mix instead they form a front, …
Read More »What is a culture and sensitivity test?
A collection of a urine sample, blood sample or other body fluid samples are cultured in medium and analysed with for sensitivity. A “C&S” is a diagnostic lab procedure used to identify the type of bacteria and to determine which antibiotics can successfully fight an infection. C&S is primarily used to find bacteria. The absence of bacteria does not mean …
Read More »What is a Csa climate?
Unless you are a meteorologist (a person who studies the weather), it is unlikely that you will know that this is, in fact, a coded description of the climate of the Mediterranean regions. Devised by a Russian meteorologist, Vladimir Koppen, in the early 20th century, the code (see below) is based mainly on temperature and rainfall and is now used …
Read More »What is a cryosurgery?
It is the technique of using extreme rapid cooling to freeze tissues, thereby destroy them. Rapid cooling to temperature below freezing point produces irreversible cell damage and cell death occurs at -20 to -90 degree Celsius. Freezing produces white areas of necrosis. It is applied in the treatment of malignancies, vascular tumours and aggressive tumours.
Read More »What is a Cotton Candy?
Cotton Candy is a soft confection that is made from sugar that is heated and spun into slim threads that look like a mass of cotton. It was invented in 1897 by William Morrison and John C Wharton, candy-makers from Nashville, Tennessee.
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