Category How things work?

To build new roads, workers move huge amounts of earth and rock. They flatten high ground and fill in low places.

A machine called a scraper box is used to move earth from one place to another. It is a huge open box with a slot at the bottom. The box is slung between two diesel engines. Its huge rubber tyres are over 3 metres high.

The engine roars. The scraper lumbers over the ground. A blade at the front bites into the ground at an angle. In seconds, over 30 tonnes of earth are scraped into the box.

Powerful shovels also dig up the earth. Each scoop is as big as a bus.

The scraper box and shovels dump their loads, and bulldozers push the piles to fill in low spots. More rocks are rammed into the ground to make a solid base for the road.

Grading machines carefully level off the top layer of small stones. Another machine lays asphalt-a mixture of sand, small rocks, and tar. Finally, road rollers press the surface absolutely flat.

 

Picture Credit : Google

Our world is full of mechanics that help us use things, go places, and communicate. Engineers help make all this possible. Here are just a few types of engineers and what they do.

Architectural engineers

Architectural engineers develop better ways of building homes and other buildings. They also find ways to make buildings taller. They apply the latest scientific knowledge and technologies to the design of buildings. Architectural engineering as a relatively new licensed profession emerged in the 20th century as a result of the rapid technological developments. 

Chemical engineers

Chemical engineers design ways to end pollution. They create drugs to fight cancer and other illnesses, too. Chemical engineers work mostly in offices or laboratories. They may spend time at industrial plants, refineries, and other locations, where they monitor or direct operations or solve onsite problems. Nearly all chemical engineers work full time.

Civil engineering

Civil engineering is the oldest kind of engineering. Civil engineers design bridges, subways, roads, dams, and canals. Civil engineering is traditionally broken into a number of sub-disciplines. It is considered the second-oldest engineering discipline after military engineering, and it is defined to distinguish non-military engineering from military engineering.

Electrical engineers

Electrical engineers design equipment that produces electric power and sends it to our homes. They also design computer circuits and robots. Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range from circuit theory to the management skills of a project manager. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple voltmeter to sophisticated design and manufacturing software

Materials engineers

Materials engineers work out how to make the produces we use better. They develop new materials for making anything from hand tools to huge trains. They also find new ways to use the materials we already have.

Mechanical engineers

Mechanical engineers design new machines. Some mechanical engineers invent better ways of heating and cooling homes and buildings. The mechanical engineering field requires an understanding of core areas including mechanics, dynamics, thermodynamics, materials science, structural analysis, and electricity.

In many ways, engineers are helping to design the future.

 

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With a click and a whirr, a robot keeps busy in the factory. It joins steel panels together. All day long it works on brand-new cars.

Some robots push a metal pin called a rivet through metal sheets to join the pieces together. Others are welders. They heat the edges of the metal very quickly so that they melt and join together.

There are no humans working these robots. These robots work by themselves.

How are robots able to join the parts correctly every time? First, a human teaches the robot to do the job. As the human moves the different parts of the mahine in and out, up and down, reaching out and twisting around, every movement is recorded by the robot’s microprocessor. Now the robot has all these movements in its memory. It knows exactly what to do every time a car is put in front of it. As long as the cars are put in exactly the same place each time, the robot will move into action and carry out exactly the right movements for riveting, welding, or even spray-painting.

 

Picture Credit : Google

Tall trees in the forest sway in the wind. So do tall skyscrapers in the city but you just don’t notice it as much. So how do these very tall buildings stay up?

The walls of a skyscraper are made of stone, concrete, glass, or metal. Under the walls is a frame of concrete or steel. This frame is strong enough to hold up the walls and floors. But it can also bend very slightly in the wind-like trees do. A tall tree has deep roots that hold the trunk and branches. Tall buildings have deep foundations. The foundation holds the steel girders in the ground.

The builders dig down until they find solid rock to build. The builders dig down until they find solid rock to build the foundation on. If there is no rock and the ground is soft, the basement is built on piles. Piles are deep holes bored into the ground. The holes are filled with steel and concrete. This gives the building a sturdy base to rest upon.

 

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Thanks to bridges, rivers and lakes will not interrupt a journey. People build bridges to make it easier to cross rough land or water. There are thousands of bridges in the world, but only five basic kinds: beam, arch, suspension, cantilever, and cable-stayed bridges.

Do you think bridges could be made out of glass? Inventors are working on this idea now. Concrete used in bridges is worn down by salt, ice, and wind. The steel used to make the concrete stronger often rusts. But a special glass called fibreglass is very strong. When glass fibres are held together by a type of “glue” ice, and wind. The steel used to make the concrete stronger often rusts. But a special glass called fibreglass is very strong. When glass fibres are held together by a type of “glue” called resin, they become stronger than steel or concrete. Fibreglass is also lightweight and can be easily shaped.

Beam bridge: This can be made of wood, steel, or concrete.

Arch bridge: A beam bridge can break easily in the middle. But a curving arch helps to carry the load on the bridge.

Suspension bridge: The roadway is suspended, or hung, from long steel cables. This type of bridge can be much longer than other types.

Cantilever bridge: One or more independent beams joined by a centre span make a cantilever bridge.

Cable-stayed bridge: This is one of the newest kinds of bridge designs. It takes less concrete or steel than a beam bridge. And it fits across narrow rivers better than a suspension bridge.

 

Picture Credit : Google

People have been using bridges to cross water for thousands of years. The earliest bridges were tree trunks. A tree growing near the bank was chopped down so that it fell across the river. Then people walked across on it. In the jungles of South America, for a long time people have made bridges out of the vines that grow there.

The ancient Romans built arched bridges out of stone. Many of them are still used today! Some bridges are still made in the same way,

Bridge-builders build strong columns, called piers, on each side of the arch. Then a strong frame is made out of wood between the piers. The arch stones are laid on top of the frame. Each stone is wedge-shaped-it is wider at the top than at the bottom. The last stone, which fits in the middle of the arch, is called the keystone. When the keystone is pushed into place, the wooden frame is taken away.

The arch will then stay in place by itself. Each stone is pressing against the next, so they hold one another up.

 

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You are building a road but a mountain is in the way. Could the road be built over the mountain? That would be rough travelling. What about going around? That would take longer-to build it and to drive on it. What about digging a tunnel? A tunnel is the shortest route, and there are many ways to build one.

Tunnels built through hard rock are usually blasted. Workers use explosives to blast each section of rock. Then they build supports in the newly opened part of the tunnel to keep rock from falling in.

Huge boring machines tunnel through clay or soft rock. As steel tubes dig through the ground, the machine “swallows” the earth and rock. The earth is dumped at the back of the machine the tunnel opening where trucks can haul it away. Reinforced concrete or steel is used to make the floor, walls, and roof of the tunnel.

Cut-and-cover tunnels are built close to the surface. Workers dig a deep trench. Then they build a floor, walls, and roof of reinforced concrete. When the concrete has hardened, the area around the concrete is filled to street level.

The mountain is no longer in the way. You simply drive right through it.

 

Picture Credit : Google

Aeroplanes get into traffic jams just in the same way cars do-especially around busy airports. But people called air traffic controllers know where each plane is located. They use radar to help them direct air traffic.

Radar allows the controllers to find planes that are too far away to see. And radar does this at night and in rain, fog, or snow.

A radar set sends out radio waves. When the radio waves hit a flying plane, or even a raindrop, they bounce back to the radar set. This makes spots of light appear on the tracking screen.

The moving spots of light tell a controller where the object is. They know how far away it is, how high it is, how fast it is moving, and which way it is going. Then the controllers can direct the air traffic, much as police officers direct road traffic. They make sure each plane follows a safe path when flying, taking off, or landing.

The planes have radar sets, too. The pilot can look at the radar to make sure that no violent storms or other planes are dangerously close.

 

Picture Credit : Google