Category Science

HOW MININGS ARE DONE TO GET GEMS FROM EARTH?

Most diamonds come from very big and deep mines. Often the mines are in the underground ‘pipes’ of extinct volcanoes. Firstly, the top rocks are removed to make a pit. Next, huge shafts are driven beneath the pit to reach the diamonds. On the south-west coast of Africa, another type of diamond mining takes place. There, diamonds lie buried in an ancient pebble beach now covered by huge sand dunes. Over 70 million tonnes of sand and pebbles have to be removed to extract half a tonne of diamonds.

Gems like opal, topaz and emerald mostly come from very small tunnels or gravel pits close to the Earth’s surface. The earth is scooped out of the pit, washed and sieved, and any gems are hand-picked from the sieve.

Some mines are extremely deep. You can see one of the mining levels in big diamond mine. Huge pits are cut out of the solid rock so that shattered rock falls through onto railway trucks running through a tunnel. Australian opal miners actually live inside mines. It takes a lot of work to free the gems from very hard rock. People also search the rock waste dumps hoping to find opals the miners may have overlooked!

Separating diamonds

Around one gramme of diamond crystals is taken from an average of about 22 tonnes of rock — the same weight as five adult elephants. It is only because diamond has special properties that such a tiny amount can even be detected and removed.

Nearly all the diamonds that are recovered are less than 3 cm across but even 1/2 cm crystals are ‘caught’ by the grease on the conveyor belt. Diamonds can also be spotted because they glow in X-rays.

Diamonds are cleaned and sent to the sorting room, then weighed and locked up.

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WHAT ARE GEMSTONES?

Gemstones are made from rare crystals that have been cut up and polished. They are usually hard and clear, or colourful. Gemstones are extremely valuable because of their beauty and rarity. Usually when we think of gemstones we imagine a jeweller’s shop window, or a beautiful ring or necklace. Polished gemstones are set into jewellery and decorative objects.

Hard or clear crystals are not only used to make jewellery, they are also used in factories, spacecraft and lasers.

Natural gemstones are found in the Earth. Crystals in the Earth’s rocks are called minerals. Gems made from these minerals are called natural gemstones. Artificial gemstones are made from glass and from crystals made in laboratories and factories. Gems of all kinds are often made to imitate more valuable gemstones.

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HOW DO GEMS ARE FORMED IN EARTH?

The Earth’s rocks are moving, squashing and often melting together. It is in this turmoil that gems are formed. The rocks are a mixture of minerals which are themselves made up of chemical elements. Atoms of chemical elements, such as carbon, oxygen and silicon, join up to make tiny building blocks. These fit together in neat regular patterns to form ‘crystals’.

Exactly what type and size of crystal forms depends on the chemical elements present, the temperature of them and the pressure exerted on them. Natural gems are found as clear or coloured crystals embedded in rock. They are also found as big crystals lining cracks or cavities in the Earth’s surface layer, or ‘crust’. Some gems are washed along by rivers and may then be picked out.

How gems are formed

Some gem crystals, like garnet, grow in solid rock as it squashes beneath moving mountains. Others, such as tourmaline, are formed in veins beneath the Earth’s surface.

Stones such as agate grow in volcanic rocks at the surface. Gems like ruby grow deep down where molten rock ‘cooks’ the Earth’s crust. Diamond crystals grow way down, around 160 km beneath the surface.

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WHAT IS AN ABACUS?

An abacus is a frame of beads used in China and neighbouring countries for making calculations. A skilled abacus user can produce answers to some calculations almost as quickly as someone using an electronic calculator.

The word abacus is derived from the Latin word abax, which means a flat surface, board or tablet. As such, an abacus is a calculating table or tablet. The abacus is the oldest device in history to be used for arithmetic purposes, such as counting. It is typically an open wooden rectangular shape with wooden beads on vertical rods. Each bead can represent a different number. For simple arithmetic purposes, each bead can represent one number. So, as a person moves beads from one side to the other, they would count, ‘one, two, three’, etc.

An abacus can be used to calculate large numbers, as well. The columns of beads could represent different place values. For example, one column may represent numbers in the hundreds, while another column may represent numbers in the thousands.

One of the most popular kinds of abacuses is the Chinese abacus, also known as the suanpan. Rules on how to use the suanpan have dated all the way back to the 13th century.

On a Chinese abacus, the rod or column to the far right is in the ones place. The one to the left of that is in the tens place, then the hundreds, etc. So, the columns are different place values and the beads are used to represent different numbers within those place values. For addition, beads on the suanpan are moved up towards the beam in the middle. For subtraction, they are moved down towards the bottom or outer edge of the suanpan. The rules of use are a bit more intricate and complicated, but this is the general idea of how one is used.

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WHAT IS GEOMETRY?

Geometry is the branch of mathematics that is concerned with points, lines, surfaces and solids, and their relation to each other. Shapes, both flat and three-dimensional, are an important part of geometry. When we describe something as geometric, we mean that it has a regular, often angular pattern of lines or shapes.

Geometry is a term used to refer to a branch in mathematics that deals with geometrical objects such as straight lines, points and circles and other shapes. However, circles are the most elementary of geometric objects. The term geometry was derived from a Greek word, ‘geo’ which means earth and metron, meaning measure. These words reflect its actual roots. However, Plato knew how to differentiate the process of mensuration as used in construction from the philosophical implication of Geometry. In essence, Geometry in Greek implies earth measurements. Geometry was first organized by Euclid a mathematician who was able to arrange more than 400 geometric suggestions. Being one of the early sciences, it is the substance of most developments and it was believed that it has been in use way before in Egypt. Evidence shows that geometry dates back to the days of Mesopotamia in 3000 BC and is attributed to numerous developments since its discovery.

Geometry is not just a math topic created to make your life harder. It is a topic that was developed to answer questions about shapes and space related to construction and surveying. It answers questions about all the different shapes we see, such as how much space an object or shape can hold. Geometry even has application in the field of astronomy, as it is used to calculate the position of stars and planets. Over time, different people contributed new and different things to grow geometry from its basic beginnings to the geometry we know, use and study today.

The first written record that we have of geometry comes from Egypt back in 2000 BC. Some of the earliest texts that have been discovered include the Egyptian Rhind papyrus, Moscow papyrus and some Babylonian clay tablets, such as the Plimpton 322. These early geometry works included formulas for calculating lengths, areas and volumes of various shapes, including those of a pyramid.

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WHAT ARE MATHEMATICAL FORMULAE?

Mathematical formulae are useful rules expressed using symbols or letters. In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a chemical formula. The informal use of the term formula in science refers to the general construct of relationship between given quantities. The plural of formula can be spelled either as formulas (from the most common English plural noun form) or, under the influence of scientific Latin, formulae (from the original Latin).

In mathematics, a formula generally refers to an identity which equates one mathematical expression to another with the most important ones being mathematical theorems. Syntactically, a formula is an entity which is constructed using the symbols and formation rules of a given logical language. For example, determining the volume of a sphere requires a significant amount of integral calculus or its geometrical analogue, the method of exhaustion. However, having done this once in terms of some parameter (the radius for example), mathematicians have produced a formula to describe the volume of a sphere in terms of its radius: V = 4/3nr3

Having obtained this result, the volume of any sphere can be computed as long as its radius is known. Here, notice that the volume V and the radius rare expressed as single letters instead of words or phrases. This convention, while less important in a relatively simple formula, means that mathematicians can more quickly manipulate formulas which are larger and more complex. Mathematical formulas are often algebraic, analytical or in closed form.

In modern chemistry, a chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols, numbers, and sometimes other symbols, such as parentheses, brackets, and plus (+) and minus (?) signs. For example, H2O is the chemical formula for water, specifying that each molecule consists of two hydrogen (H) atoms and one oxygen (O) atom. Similarly, O?
denotes an ozone molecule consisting of three oxygen atoms and a net negative charge.

In a general context, formulas are a manifestation of mathematical model to real world phenomena, and as such can be used to provide solution (or approximated solution) to real world problems, with some being more general than others. For example, the formula F = ma is an expression of Newton’s second law, and is applicable to a wide range of physical situations. Other formulas, such as the use of the equation of a sine curve to model the movement of the tides in a bay, may be created to solve a particular problem. In all cases, however, formulas form the basis for calculations.

Expressions are distinct from formulas in that they cannot contain an equal’s sign (=). Expressions can be liken to phrases the same way formulas can be liken to grammatical sentences.

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