How can shipwrecks be prevented?

How can shipwrecks be prevented?

There are many ways to reduce the chances of accidents happening at sea. Buoys, which are like floating road signs in the sea, warn ships of rocks under the water and help them to enter a harbour safely. Lighthouses have also been used for hundreds of years to warn ships of danger, and guide them to safety.

Ships signal with their horns to tell each other which way they are turning. Sea charts and maps can help by showing where rocks and sand banks are, so that a ship can avoid them. Today, many ships have a technology called Global Positioning System, which shows them their exact location on the globe.

Weather departments also play an important role by warning ships of storms, hurricanes high winds and sea conditions, so that precautions can be taken, and shipwrecks avoided.

How big is the ocean?

How big is the ocean?

The ocean is absolutely huge! It covers two thirds of the earth, which means there is twice as much water as there is land. The five oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Arctic Ocean and the Antarctic Ocean.

The Pacific Ocean is the biggest ocean. It reaches half way round the world, and is bigger than the Indian, Atlantic and Arctic Oceans. The Indian Ocean is smaller than the Atlantic, but it is a little deeper.

How big is the Earth?

How big is the Earth?

The distance around the Earth, that is it's circumference at the equator is 40,091 kilometers. The diameter (the distance across the centre of the Earth) at the equator is 12,756 kilometers. The Earth is slightly smaller when measured between the poles ( 12,713 Kilometers), so it is not an exact sphere. If the Earth is weighted on a weighing machine it would be nearly 6,000 million million million tones.

How are waves formed?

How are waves formed?

When you go to the beach, don’t you love to watch the waves crashing on to the shore? Do you know how these waves are formed? When the wind blows across the surface of the ocean, it pulls the water upwards. Gravity will pull it down again, creating ripples. If the wind is strong enough, and blows far enough over the water, these ripples build into waves. On calm days, waves are small. Waves grow bigger as the wind grows stronger. As they travel great distances, waves become more and more powerful.

How are the shells of shell fish different from those of crabs?

How are the shells of shell fish different from those of crabs?
The shell of s shell fish grows with it. A crab, however, has to keep replacing its shell as it grows. This is called moulting.

How are the oceans poisoned?

How are the oceans poisoned?

Oceans and seas have the ability to clean themselves to some extent. But as pollution of the oceans and seas increases, they are no longer able to do so. In this way, earth’s are slowly being poisoned and dying away.

How are shipwrecks recovered?

How are shipwrecks recovered?

Shipwrecks are difficult to find. You need a boat with sonar and other special equipment. Remotely Operated vehicles on board the boat have cameras that send back pictures of ocean floor. Once a shipwreck is found, it may be possible to raise it off the sea bed by using winches and inflatable balloons. It is a difficult task that must be done very carefully.

How are seashells formed?

How are seashells formed?

Seashells are the external skeletons of sea creatures called mollusks. Mollusks include creatures such as scallops, oysters and sea snails. Shells support their soft bodies and protect them from their predators and the environment. The shell is formed mostly from crystals of calcium. Some shells have chambers that can be filled with water or air, and allow the owner to float or sink as required.

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How are pearls formed?

How are pearls formed?

Pearls are produced by oysters and mussels in response to irritation. When a piece of grit (gravel or sand) gets between the oyster’s shell and its skin (mantle), natural pearls are formed. This happens when tissues surround the grit to produce mother-of-pearl layers. Pearls are artificially produced by inserting particles into the clam.

How are oil and gas reservoirs in the sea identified?

How are oil and gas reservoirs in the sea identified?
Valuable reservoirs of oil and gas lie hidden in rocks on the seabed, and it can be tapped by drilling through the rocks. But only some kind of rocks contain oil and they must be located in water that is shallow enough for the drilling to reach it. These reservoirs are identified by means of shock waves sent through the seabed and the returning signals distinguish between the rock layers.

How are islands formed? What are archipelagos and coral reefs?

How are islands formed? What are archipelagos and coral reefs?

Some islands are the tops of undersea volcanoes. Others are pushed up by a volcano. Islands like the British Isles are formed when a continent breaks up and a part of it is cut off by water. A chain or group of islands is called an archipelago. The world’s biggest archipelago is Indonesia, which is made up of more than 13, 000 islands!

Coral reefs are made up of the limestone bodies of tiny coral animals. They are usually round in shape, and have a lagoon in the centre.

How are creatures adapted to live in the dark depths of the ocean?

How are creatures adapted to live in the dark depths of the ocean?

The deep ocean is a very inhospitable place to survive. The temperature of the water is icy, sunlight does not ever reach below 1000 feet, and the pressure of the water is crushing. To survive these hostile conditions, creatures have special adaptations. For instance, many predators of the deep sea have huge mouths and stomachs that can stretch to take in huge meals. This is necessary because the chances of coming across other animals to prey upon are rate and each opportunity for a meal must be taken, however large.

The light in the deep ocean comes mostly form the photophores located in different parts of the bodies of the creatures that live there. This light is used to attract or locate a prey or a mate or to confuse an enemy. Deep-sea fish have a natural buoyancy which makes them hover when not swimming in the tremendous pressure. This is made possible because they have thin, lightweight skeletons and muscles.

The red colour of the prawn’s body is a good camouflage in the deep. In the dim light, red appears black and they blend into the background. At depths that are still below, prawns are almost colourless as there is no need for camouflage. The total blackness there hides them from predators.

How are birds affected by sea pollution?

How are birds affected by sea pollution?


Birds are some of the most sensitive creatures to sea pollution. Oil from an oil spill is readily absorbed into birds’ feathers. It is the feathers that trap heat to keep a bird’s body cools rapidly, and the bird dies from cold.

Birds are also poisoned by the oil when they try to clean the sticky oil from their feathers with their beaks. Oil spills also destroy the bird’s natural sources of food so that it starves to death.

Tell about underwater explorations?

Tell about underwater explorations?
Man has always tried to explore what is above and below the firm earth, the sky and the deep seas. Exploring the oceans has never been an easy task. Till the present century, the only way to do that was by lowering instruments on lines from ships. Sonars, which used sound waves to detect details on the sea bed became popular after the First World War. Other instruments which are used for exploration include thermometer, current meter and cameras. Nowadays, oceanography is mostly done from satellites and it can measure the height of waves, temperatures etc, and can even detect the presence of shoals of fish!

In spite of the use of instruments, people want to go down to the depths of the sea to explore it for themselves. Diving suits were developed for the purpose and air for the diver was supplied from the ship by means of a hose. The SCUBA gear, made later, improved upon this and carried its own air supply. Divers have to be specially trained and prepared to adapt themselves to the great pressure of water on their bodies. Along with these developments, inventors also made containers to carry men breathing air at normal pressure under the sea.

In which ocean is the saltiest sea?

In which ocean is the saltiest sea?
The Red Sea in the Indian Ocean has the saltiest sea water in the world. Part of it is known as the Dead Sea, and is so salty that nothing can live in it. The water of the Dead Sea is very buoyant because it is so salty. This means that people can float in it with no effort at all.

In what ways are seaweed utilized?

In what ways are seaweed utilized?
Seaweed is used as food and is very popular in China and Japan. On seaweed farms, red seaweed is grown in the sea on bamboo poles, collected and dried. Laver is bread made from seaweed in Wales. A jelly like substance called agar is made from seaweed and used in foods.

Besides food, what useful does the sea supply?

Besides food, what useful does the sea supply?
The seas are huge storehouses of valuable items. Apart from food, the waters and rocks supply many chemicals and minerals useful in medicine and industry. salt, magnesium, iodine and bromine are extracted from seawater. From shallow seas, dredging vessels haul up sand, gravel and tin and even diamonds. Oil and gas is piped up from the depths of the sea in many parts of the world.

Nowadays, special ships are being developed to suck up millions of metallic lumps from the ocean floor. These lumps, called manganese nodules will yield not only manganese but also cobalt, copper nickel and other useful substances. As the mines on land become exhausted, we will have to depend more and more on the mines of the sea.

Does the change in mother's food affect the baby?

Whatever the nursing mother eat will be secreted in her milk, but in insignificant quantities. Generally if the mother tolerates a particular food item well the baby also tolerates it well.

A normal well nourished mother secretes about 500 ml of milk daily for the first 6 months to one year and after that the quantity slowly comes down. Whereas an undernourished mother's milk is insufficient in fats and vitamins and inadequate for the baby also.

Eating fishes and vegetables contaminated with pesticides may cause problems in the baby because of their secretion in the milk. Eating spices, condiments, chocolates, onions, tomotoes may cause loose stolls in the babies.But the problems are plenty in the baby of a mother who smokes, drink alcohol and abuses the drugs. Almost all the drugs are excreted in the breastmilk and they will have their effect on the body.

For medical reasons if the mother has to take certain drugs like anticoagulants, anti-cancer drugs, antithyroid drugs, radioactive drugs, purgative etc., seh has to stop feeding her baby as long as she is on those rugs.

Does frequent switching on/off of a fluorescent lamp reduce its life?

The life of a fluorescent lamp is essentially determined by life of the cathode filament it uses. A conventional fluorescent lamp employs closely wound coil of tungsten wire as filament. Upon switching on the lamp, electric current passing through the filament will raise the temperature of the filament that in turn will generate thermions (electrons generated by a thermal process). Thermions are necessary to initiate electric-discharge through the column of the fluorescent lamp.

Frequent switching on/off the fluorescent lamp occurs through several cycles of filament heating and cooling. If the cycles of heating and cooling of the filament are too frequent this may result in tremendous loss of oxide coating (at the rate of 10-20 micro-grams/cm{+2} per cycle).

The loss of oxide coating in the cathode filament through rapid on/off (heating/cooling) operations will lead to poor performance of the filament in generating thermions to initiate the discharge process. This in turn will reduce the life of the fluorescent lamp. Life of a conventional fluorescent lamp usually rated for several thousand hours of continuous burning can be halved or made still less, just by frequent switching on/off.

Do some ships disappear with out a trace?

Most ships are used for years and years without any mishap. However, accidents can happen at sea and even the biggest ship can disappear without a trace. The ship can be overturned by a giant wave. Because of its huge size and weight, it will then sink to the bottom of the sea quickly, before anyone can send a call for help through its radio.

Ships have also disappeared during good weather, and to this day the mystery of how they were lost and where they have gone has not been solved.

Do some fish give off electric shock?

Yes. There are indeed fish, which give off electric shocks to protect themselves or to stun their prey. The torpedo ray is the fish with the biggest shock.

Do plants grow at the bottom of the sea?

Many types of algae grow on the ocean bed. But the deep ocean is too dark for plants to grow as sunlight cannot penetrate deep into the sea.

Do mermaids really exist?

It is highly unlikely that mermaids exist. What is likely is that sailor might have glimpsed a plant eating marine mammal called the manatee. The manatee floats upright while nursing its young, using its front feet to cradle its baby. From a distance, an imaginative sailor might think it is woman with a baby in her arms.

Do animals also have blood groups like humans?

In man blood group is applied to single factor. This factor is agglutinogen and is also called antigen. It is found on the surface of red blood corpuscles.

Accordingly a person with `A' antigen is designated as a person with A-group, with `B' antigen as B-group, with both A and B antigens as AB-blood group and a person without any antigens is designated as O-blood group.

In the case of animals blood group is applied to combinations of blood factors. So it is preferable to call it as blood group systems rather then blood groups. Each system has many factors, which are together called blood group factors.

Dr. J. Moustgaard, of the Royal Veterinary & Agricultural College, Copenhagen has identified in cattle ten group systems namely A,B,C,FV,J,L,M,SU, Z and R'S'. Except J and L, all the other group systems have more than one group factor. For example the group factors of the group system A are designated as A{-1}, A{-2}, D, H, Z'.

The grouping factors are particular serum proteins. Acquiring of each protein is an inherited character. So examination of blood sample from within a breed might eventually prove a very useful means of selection. It might also indicate what mating could be expected to result in infertility.

The B-group system only has greater number of grouping factors. It has nearly 27 group factors, which are called phenogroups. Some of these are unique to particular breeds.

They are particularly valuable in determining incorrectly stated parentage. In dogs serum major groups have been recognised in the USA and they are referred to as A to G.

In veterinary practice blood transfusion is used in cases of haemorrhage and shock and to a lesser extent as part of the treatment of certain infectious diseases.

In cattle the donor and recipient are usually in the same herd. This fact lessens the risk of introducing infection and incompatibility does not arise.

But normal antibodies against the blood group factor-J are sometimes found in cattle. Thus if the donor's blood is J-positive and the recipient's blood contains normal antibody called anti-J the so-called transfusion reaction might be expected immediately following blood transfusion. These reactions are dyspnoea, muscular twisting, increased salivation and circulatory disturbances.

However, if an animal has been exposed to repeated blood transfusions, a different situation will arise. The animal will now have formed antibodies against the blood group antigens it does not have itself. It is therefore by no means unlikely that the blood of donor and the recipient are incompatible.

If this is so, transfusion will set off strong transfusion reactions. Such reaction can occur on the second or on subsequent blood transfusion.

Do all seas have tides?

Tides are caused due to the pull of the moon, and to a much smaller extent, the sun. In general, the larger the body of water, the more noticeable the tide. The height of the tide depends on the size, shape and depth of the sea in a given location. In enclosed seas like the Mediterranean Sea, there is hardly any tide at all, because it is surrounded by land on all sides. The rise and fall of the water may be only a few centimeters.

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Do all rivers run into the ocean?

Surprisingly enough, they don’t! The rivers flowing south from the Tassili Mountains in North Africa slow down to a trickle and disappear in the searing heat and scorching dryness of the Sahara sands. Sadly, even some of the world’s great rivers that used to flow into the ocean now fail to reach it. This is caused by water evaporation from dams and irrigation canals that lead to massive water loss.