Monthly Archives: June 2003

The Story of Phosphorus

 

   In today’s VERITAS we will study the remarkable element Phosphorus.

We will study the history of its discovery and some of the properties that make it so useful and also so dangerous.

   Before the study of chemicals became a science it used to be a field for people with more monetary interests. Alchemists were about the only people who studied chemicals and they had only two aims: to find a way to make gold from other metals/elements and to find a chemical that would make man immortal. Hennig Brand was just another alchemist and he was trying to find new ways of making gold. In a crazy experiment he filled a tub with human urine. He boiled it into paste. He hoped that he would heat the paste and condense the fumes and these condensed fumes would be gold.

To his disappointment he obtained a white waxy substance. But this substance had a remarkable property: it glowed in the dark. Brand had discovered Phosphorus.

The year was 1669. And this was the first element that was isolated since the days of ancient civilizations( who knew about gold, silver , iron etc).It was named phosphorus( meaning light bearer). Soon this chemical became famous with chemists the world over. Robert Boyle in England did a lot of research on it.

      If you are thinking that Alchemists were a few crazy people with some crazy interests you are wrong. Alchemy had a huge following at that time. People knew that gold was a substance and iron was a substance.

They knew that water was a substance and salt was a substance. They knew how to get salt from sea water. So they thought that they were converting one substance to another. They wondered if they could find a substance that could be converted to gold. They lacked that one critical piece of knowledge that we have : gold is an element and water is a compound.

You can get oxygen from water but Gold is not composed of anything else.

You cannot create a gold atom from another element’s atom. People at that time did not know about atoms and about the impossibility of such a conversion. Even the great scientist Isaac Newton was an Alchemist. When he was not doing Physics he was trying to mix substances to try and make gold.

      For about a 100 years the only way to extract Phosphorus was from urine.

In 1770 some scientists realized that animal bones contained Phosphorus and found ways of extracting it.

 Phosphorus has a tendency to burst into flames. There are 4 kinds of Phosphorus: white, red, black and violet. White Phosphorus is the most volatile. In its pure form it has to be carefully controlled. It is usually stored in oil baths. As soon as it comes in contact with air it bursts into flames.  This property of phosphorus inspired scientists. Red phosphorus is more stable and can be controlled more easily.

      Think for a moment about how difficult it would be to light a fire.

You need a spark. Can you imagine yourself going to a jungle and creating a fire with just rocks and dry leaves…. Now imagine doing it everyday!

The invention of matches was a great boon to mankind. It made burning fires so much easier… a routine task.   In 1827, John Walker the English chemist discovered that if he coated the end of a stick with certain chemicals and let them dry, he could start a fire by striking the stick anywhere. These were the first friction matches. In 1830, the French chemist, Charles Sauria, created a match made with white phosphorus. Sauria’s matches had no odor, but they made people sick with a ailment dubbed “phossy jaw”.White phosphorus is extremely poisonous! In 1855, safety matches were patented by Johan Edvard Lundstrom of Sweden. Lundstrom put red phosphorus on the sandpaper outside the box and the other ingredients on the match head, solving the problem of “phossy jaw” and creating a match that could only be safely lit off the prepared, special striking, surface.

Now Phosphrous is explosive and also very poisonous. 50 mg of phosphorus is a fatal dose. People started using Phosphorus in bombs and tracer bullets.

They also started making chemical weapons using Phosphrous.

In the second world war the German city of Hamburg was destroyed by phosphorus derived bombs. 80,000 phosphorus bombs and 500 phosphorus drums were dropped on Hamburg for three days. 40,000 men were killed, a further 40,000 wounded and 900,000 were homeless or missing. In three nights Hamburg was wiped out.

 Some scientists believe that Phosphorus limits life on earth. It is required by all organisms but it is extremely rare. It is a part of all bones and cells.

Recently a book on this history of this element has been released :” The Shocking History of Phosphrous: A biography of the Devil’s Element” by John Emsley.

The_alchemist

      The discovery of the glowing Phosphrous by Alchemists from urine has also been the subject of a very famous painting: “The Alchemist” by Joseph Wright (1771). A print of the painting is attached with this VERITAS mail.

 

Kanwar

 

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  Go, wondrous creature! mount where Science guides:

  Go, measure earth, weigh air, and state the tides:

  Instruct the planets in what orbs to run,

  Correct old time and regulate the Sun;

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The Limits of Ocean Depth

 

      In today’s VERITAS we shall explore the deepest point of all oceans. We will see if life can survive the extreme conditions of these depths.

      The deepest point on earth is the Challenger deep located in the Marina Trench. This is located north of New Guinea in the Pacific Ocean. The depth of this point of the ocean is about 11 kilometres(6.8 miles). So if you could place Mount Everest there, it would be submerged with 1 km of water over its peak.

      We know very little about places so deep below the sea.

Light lasts to about 200 metres below the sea. By 500 metres it is pitch dark. The top 200 metres where there is still light is called the “photic zone”. Photosynthesis can only occur in this shallow zone. Below 100 metres the temperate drops to 2-3 degrees C.

Pressure increases rapidly. For every 10 metres the pressure increases by 1 atmosphere. SO extreme conditions start even before we reach the 500 metre depth. You can imagine( or can you?) the conditions at the bottom of Challenger deep. Would life survive there? Imagine the weight of 11 kilometres of water on you!

      Yes, there is life at the bottom of the Challenger deep.

There are certain organisms which absolutely need high pressure to maintain their body processes. These are called barophilic organisms. Their cell membranes have different protein composition. Their enzymes are bound differently. Normal enzyme bindings get weak with pressure.

      So the Challenger deep has life in the form of microbes which love pressure. It also contains more complex creatures. Shrimps, scale worms and sea cucumbers are also found there.

So we see that several different kinds of creatures live there.

What do they eat? They eat smaller organisms! But it has to start somewhere! Most the life that we are familiar with starts from the sun with plants producing food from sunlight. The rest of the creatures eat plants or other plant eating creatures.

At the depth of Challenger deep what is the primary source of energy?

Sunlight cannot reach there. What is at the bottom of the foodchain?

At the bottom of the foodchain are creatures that take energy from the hot core of the earth. The Mariana Trench has chimneys and hydrothermal vents which release smoke from the hot core of the earth. These hydrothermal vents release poison gas, heavy metals, acids, and heat. Some Creatures survive by oxidizing the hydrogen sulfide that is released by these vents. This process is called Chemosynthesis. 

The rest of the creatures eat these creatures. These hydrothermal vents are home to colonies of creatures that use the stuff released from them.

      These releases from the vents may seem like food for the organisms that live in the deep. Far from it. For most of these creatures these gases and heavy metals are extremely toxic. Also these vents create extreme heat that these creatures are not used to. Liquified heavy metals can clog the mouths of these creatures killing them instantly. Only for a small set of creatures these chemicals act as food. The rest just depend of these creatures and these stay away from the vents.

      Fish has been found till a depth of 8.5 kilometres( 5.2 miles) in the Challenger deep. These fishes have no eyes( no light so no eyes).

      How deep has man gone? The deepest that a man could descend was to a depth of just 90 metre from the Challenger deep floor.

Submersibles with robotic arms have touched the ocean floor several times.

      Some beautiful lines from Lord Byron’s poem: The Sea:

 

       Roll on, thou deep and dark blue Ocean,–roll!

       Ten thousand fleets sweep over thee in vain;

       Man marks the earth with ruin,–his control

       Stops with the shore;–upon the watery plain

       The wrecks are all thy deed, nor doth remain

       A shadow of man’s ravage, save his own,

       When, for a moment, like a drop of rain,

       He sinks into thy depths with bubbling groan,

      Without a grave, unknelled, uncoffined, and unknown.

 

Kanwar     

 

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  Go, wondrous creature! mount where Science guides:                 

  Go, measure earth, weigh air, and state the tides:                 

  Instruct the planets in what orbs to run,                          

  Correct old time and regulate the Sun;                              

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