StopLearnStopLearnA triangle may be defined as a plane figure contained by three straight lines, known as the sides of the triangles. One of the sides, usually the one most nearly horizontal, is identified as the base.
A triangle, as its name implies, has three angles. The two angles at the ends of the base are called base angles. The third angle, which is opposite the base, is called the vertical angle is formed is termed the vertex of the triangle.
The sum of the three angles of any triangle is 1800.
You can check this statement by drawing a triangle in any manner you like. Measure the three angles formed using a protractor. Sum the angles and confirm that they add up to 1800.
The altitude or height of a triangle is the perpendicular distance from the vertex to the base.
Triangles are classified according to the magnitude of their angles or according to the length of their side.
An acute angle triangle is one which has each of its three angles less than right angle.
A right angled triangle is one which has one of its as a right angle. The side of the triangle opposite the right angle is called the hypothenuse.
An obtuse angled triangle has one has one of its angles greater than a right angle.
An equilateral triangle is one which has its sides equal.
(Note: The three angles are also equal, each being 600.)
The sides are also equal i.e., AB = BC =AC. An isosceles triangle has two of its sides equal.
(Note: The two angles of the feet of the equal sides are also equal.)
A scalene triangle is one in which no side is equal to another.
ASSESSMENT
Topic: Material and Their Common Uses (cont’d)
Contents:
Ceramics –
The basic material for the production of ceramics is clay, this is dug out of the ground. After water is added, the mixture is shaken and sieved so that unwanted material, such a stones, is removed. When the clay has settled and drained it is allowed to dry until it is suitable to be worked on.
Clay can however be bought already prepared. Red clay contains iron oxide. It has a fine texture and is fired (baked) in kilns at temperature between 9000C and 12000C. It is used for making earthenware utensils.
Grey clay has a small amount of iron oxide. It is fired at about 12000C and is biscuit coloured. It is used to make stoneware utensils.
China clay is obtained from kaolin and is white in colour. It has very fine particles and is used for delicate utensils.
Articles made from clay usually need to be fired twice. The first time the temperature is about 5000C, this drives off excess moisture. The second time, firing is at a higher temperature, and this hardens the utensils.
Uses of Ceramics
Ceramics can be used for many things. Due to the fact that ceramics can withstand very high temperature, they are used in making furnaces. A furnace is a structure or apparatus in which a lot of heat is generated. While the water in an electric kettle boils at about 1000C, iron melts at about 15360C. Ceramics can withstand even higher temperatures.
Ceramics can carry heavy loads. As a result of this property, we use bricks and cement blocks to build houses. The walls of any building carry the roof of the building, the top floors, people and decorations.
Most electric poles are made from concrete which is a type of ceramic. The insulator between the lines is also ceramic. Other ceramics are the windscreens of vehicles, ordinary looking glass, television screens and ashtrays. A modern toilet is built entirely with ceramics. The walls are made from concrete blocks, which are ceramics, while the tiles, sinks, baths and toilet bowls are all made of ceramics.
Common types of clay mined include: common clay, kaolin (China clay), bentonite, ball clay, fuller’s Earth, and fire clay, and each has a number of different uses:
Uses of Rubber
Think of rubber and you probably think of elastic bands, car tires, or pencil erasers. But this super-stretchy material actually finds its way into tens of thousands of different products—everything from rubber stamps and waterproof shoes to dishwasher hoses.
Rubber is a material which can stretch and shrink. It is a polymer and it can be produced from natural sources (eg. natural rubber) or can be synthesised on an industrial scale. Sometimes the word means only natural rubber (latex rubber). Natural rubber is made from the white sap of some trees while the other is called synthetic rubbers, made by chemical processes.
Rubber, in one form or another has been used since the times of old, evidence of its use going back 2,000,000 years or more. In those days the substance was derived naturally from the rubber tree. Individuals would then use it to make balls, and to waterproof handmade buckets, pails and more. As time went on more and more uses for rubber was discovered inspiring the invention of synthetic rubber because the natural alternative could not keep up with the growing demand. Every year an approximated 4 million tons of natural rubber and 7 million tons of synthetic rubber are produced to make more than 50,000 different products that we use on a daily basis worldwide.
Natural rubber production begins with the tapping of the matured rubber trees of South East Asia and Africa. Workers tap the trees by making an incision which cause the slow flow of the milky fluid called latex, after enough of the latex is collected in pails the water is then removed from it and the latex is then turned into raw rubber. There are approximately twenty different types of synthetic rubber used today including silicone rubber,acrylic rubber and butyl rubber. the production of this type of rubber consists of the adding of materials like petroleum, crude oil and different types of gases.
Today, rubber is as widely used as wood and this is largely due to its beneficial properties like strength, long lasting, water resistance and heat resistance all these benefits makes this material perfect for tire production, in fact a large percentage of rubber production goes into the automotive industry. Other benefits like being non slip, soft, durable, resilient makes this material the first choice for playground equipment, shoes, mats, flooring, healthcare supplies, household supplies, balls, toys and thousands of other rubber products. Rubber comes in a large variety of colors, styles and textures making it extremely diverse. Used rubber tires are often recycled to make other items like mulch, shoes, bags, jewelry and coats. It is safe and reliable and seen as a valuable material by many.
Uses of Plastics
Plastic when hot can be shaped by pressing or squeezing. There a few natural materials that are plastic but most are man-made. There are very many types of plastic with different purposes and these are gradually replacing wood and metals for many articles. Plastic are made from chemicals obtained from natural sources such as water, air, oil, gas and coal. Some of these chemicals have complicated formulae and long names which are so difficult to remember that the makers often call them by simple names, or trade names.
Thermoplastics
Thermoplastics are plastics which become soft when they are heated. They harden again as they cool, but may be reheated, when they will become soft again.
Properties of Plastics
There are some plastics which you can see through easily, and they are said to be transparent like a glass. Others allow strong light through but you cannot see through them. They are said to be translucent, like white plastic carrier bags. Some plastics do not let light through at all, these are said to be opaque. To check whether a plastic is translucent, put it in front of a torch, switch on the torch and look to see whether any light is coming through.
Uses of Plastics
Plastic means something that can be shaped by pressing or squeezing. There are a few natural materials that are plastic but most are man-made. There are very many types of plastics with different properties for different purposes and these are gradually replacing wood and metal for many articles. Plastics are made from chemicals obtained from natural sources such as water, air, oil, gas and coal. Some of these chemicals have complicated.
ASSESSMENT
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