Category Geology

Why does the sea flow in and out?

Twice a day, the sea washes on to the shore at high tide. Then it flows back out again at low tide. The tides are caused by the Moon and Sun pulling the sea into giant bulges on either side of the Earth.

Amazing! If all the coasts were straightened out, they’d stretch round the Earth 13 times. At 90,000 kilometres, Canada has the longest coast.

Why are beaches sandy?

Sand is made from tiny fragments of rock and shells, crushed up by the wind and water. Sand is usually yellow or white. But some sand is black because it contains volcanic rock or coal.

How are cliffs carved out?

Along the coast, the rocks are worn away by the force of the waves. As the waves crash against the shore, they carve out cliffs, caves and high arches. Sometimes an arch collapses, leaving a stack, or pillar, of rock.

Is it true? White horses swim in the sea.

Yes. But they’re not real horses. They’re the white, foamy tops of the waves as they gallop towards the shore.

Picture Credit : Google

How big is the sea?

The sea is absolutely huge! Salty sea water covers about two-thirds of our planet so there’s far more sea than land. The sea lies in five oceans — the Pacific, Atlantic, Indian, Arctic and Southern Oceans.

Amazing! The first person to set sail around the world was Ferdinand Magellan. He set off from Spain in 1519. Magellan died but one of his ships made it back three years later.

Which is the biggest ocean?

By far the biggest ocean is the vast Pacific. It alone covers a third of the Earth. At its widest point, between Panama and Malaysia, it stretches almost halfway around the world.

Is it true? The Arctic is the warmest ocean.

No. The Arctic’s the coldest ocean of all. For most of the year, it’s covered in ice.

Why is the sea salty?

The sea’s salty taste comes from ordinary salt. It’s the same stuff you sprinkle on your food. The rain washes the salt out of rocks on land, and then rivers carry it into the sea. The people in the picture are collecting salt left after sea water dries.

Picture Credit : Google

What are icebergs?

Icebergs are giant chunks of ice that break off the ends of glaciers and drift out to sea. Only about a tenth of an iceberg shows above water. The rest is hidden under the sea. This makes them very dangerous to passing ships and boats.

Amazing! In 1912 the luxury liner, Titanic, hit an Iceberg and sank in the North Atlantic. It was on its maiden (first) voyage from Southampton to New York.

Which was the biggest iceberg?

The biggest iceberg ever was seen near Antarctica. It was about the size of Belgium! The tallest iceberg was more than half as high as the Eiffel Tower in Paris.

Which is the longest glacier?

Glaciers are enormous rivers of ice that flow slowly down a mountainside. The Lambert-Fisher Glacier in Antarctica is over 600 kilometres long. It’s the longest glacier in the world. About a tenth of the Earth is covered in icy glaciers.

Is it true? Baby icebergs are called calves.

Yes. When a baby iceberg breaks off a glacier, it is called ‘calving’. Even smaller icebergs are called ‘bergy bits’.

Picture Credit : Google

What is used as a measure of distance covered by aircraft?

One of the challenges of international flying is handling different units of measure in different countries. In aviation, the battle between imperial and metric units continues. Feet, meters, statute miles, nautical miles, inches of mercury, millibars, hectopascal, knots, meters/second – it can get a little confusing! Read on and I’ll scramble your brain with international aviation units!

World-wide, the nautical mile (nm) is the standard for measuring the distance an aircraft travels across the ground. 

Other lateral measurements are a mess. Most of the world measures runway length in meters while North America uses feet. Most of the world measures airport visibility in meters. North America? Not nautical miles, not meters, but statute miles! Huh?? Not to worry, North America changes back to feet when measuring Runway Visual Range (runway visibility measured with a laser), while the rest of the world sticks with meters. Confused? I sure am, and I do this for a living!

 

Picture Credit : Google

Hanuman is said to be the son of the god of wind. Can you name him?

Lord Hanuman, son of Vayu (wind God) and Anjana, was very powerful. There are different versions of how he was born. One is that on Ramanavami, when Rishyashringa performed yagna, divine nectar which contained the seed of Lord Shiva was given to the three wives of King Dasharatha, the King of Ayodhya.

After consuming it, Ram, Lakshman, Bharat, and Shatrughna were born to them. But one portion of the nectar was carried away by a large bird into the sky. However, Vayu took that portion away from the bird
and brought it to Anjana. She drank it and Lord Hanuman was born.

 

Picture Credit : Google

HOW DO UNDERGROUND MINES OPERATE?

Deep deposits are reached by driving a shaft vertically into the ground. Miners descend the shaft in a lift. An air shaft takes fresh air down into the mine, where poisonous gases may accumulate. Trucks carry the mined material to a freight lift, which brings them to the surface. Trucks may also be used to take miners to the nearest deposits. Drift mines are dug where the deposit lies in an outcrop of rock near the surface. The seam can be mined directly from the surface, which is often on the slope of a hill.

Deep deposits are reached by driving a shaft vertically into the ground. Miners descend the shaft in a lift. An air shaft takes fresh air down into the mine, where poisonous gases may accumulate. Trucks carry the mined material to a freight lift, which brings them to the surface. Trucks may also be used to take miners to the nearest deposits. Drift mines are dug where the deposit lies in an outcrop of rock near the surface. The seam can be mined directly from the surface, which is often on the slope of a hill.

There are underground mines all over the world presenting a kaleidoscope of methods and equipment. There are approximately 650 underground mines, each with an annual output that exceeds 150,000 tonnes, which account for 90% of the ore output of the western world. In addition, it is estimated that there are 6,000 smaller mines each producing less than 150,000 tonnes. Each mine is unique with workplace, installations and underground workings dictated by the kinds of minerals being sought and the location and geological formations, as well as by such economic considerations as the market for the particular mineral and the availability of funds for investment. Some mines have been in continuous operation for more than a century while others are just starting up.

Mines are dangerous places where most of the jobs involve arduous labour. The hazards faced by the workers range from such catastrophes as cave-ins, explosions and fire to accidents, dust exposure, noise, heat and more. Protecting the health and safety of the workers is a major consideration in properly conducted mining operations and, in most countries, is required by laws and regulations.

The underground mine is a factory located in the bedrock inside the earth in which miners work to recover minerals hidden in the rock mass. They drill, charge and blast to access and recover the ore, i.e., rock containing a mix of minerals of which at least one can be processed into a product that can be sold at a profit. The ore is taken to the surface to be refined into a high-grade concentrate.

Working inside the rock mass deep below the surface requires special infrastructures: a network of shafts, tunnels and chambers connecting with the surface and allowing movement of workers, machines and rock within the mine. The shaft is the access to underground where lateral drifts connect the shaft station with production stops. The internal ramp is an inclined drift which links underground levels at different elevations (i.e., depths). All underground openings need services such as exhaust ventilation and fresh air, electric power, water and compressed air drains and pumps to collect seeping ground water, and a communication system.

Picture Credit : Google