This edited article about the gramophone originally appeared in Look and Learn issue number 704 published on 12 July 1975.

A child in the ‘Sixties playig  LPs on a stereo record player

“Is it a British or a German submarine? We must be able to hear the difference!”

This was the awesome task set by R.A.F. Coastal Command when they approached the Decca gramophone company during World War II. It was a secret assignment and called for a record to be produced which could be used as a training aid to familiarise airmen with the subtle differences made by the sounds of the enemy and our own submarines.

Difficult as the problem was, Decca came up with the answer – a record with such a wide range of sensitive sound that it was completely satisfactory.

Intensive research had produced an exciting new recording technique, stretching the gramophone’s capabilities to a greater extent than ever before. Adapted later for musical reproduction after the war’s end, the process became known as “ffrr” (full frequency range recording,) and Decca took it as their trademark.

It was not long after the war, that another kind of battle began, this time between the rival recording companies.

In 1948, Columbia Records of America held a Press Conference in New York to launch a revolutionary idea, invented by Dr. Peter Goldmark, called the LP (Long Playing) record. Their new 12-inch disc turned out to be made of non-breakable vinyl plastic, played at 33 and a third r.p.m. on microgrooves and lasted 23 minutes per side. It had about 250 grooves to the inch instead of about 80 in the 78 r.p.m. record.

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This edited article about the physics of cold temperatures originally appeared in Look and Learn issue number 702 published on 28 June 1975.

How the regrigerator works

The coldness of objects is measured by thermometers, the standard measuring point being the temperature at which water freezes. This is usually called the “freezing point,” and on the Fahrenheit scale this is at 32 degrees, and on the Centigrade scale it is at 0 degrees. If we say a certain temperature is below freezing point we simply mean that our thermometer reads less than 32 degrees Fahrenheit or minus some degrees Centigrade.

Things can be made cold in several ways. The most familiar way is simply to bring the thing we wish to cool into contact with something colder. If we add cold milk to hot tea the tea becomes colder. Or we can make the temperature of a glass of water fall to nearly freezing point by simply surrounding the glass with chunks of ice.

Liquids become cold when they start to evaporate. If you wet the back of your hand, and blow on it, your skin will feel quite cold as the water changes to vapour.

Air and other gases become colder when the pressure on them suddenly falls. If you place your finger over the hole in the end of a bicycle pump and quickly pull the plunger out, the air inside the pump becomes rarified, or lower in pressure, and cooler at the same time, and you can feel this with your finger.

The coldness inside refrigerators is produced through evaporation and low pressures, as special pumps reduce the pressure and special liquids are used which evaporate quickly.

Scientists have been able to make very powerful refrigerators which can produce temperatures far below freezing point.

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This edited article about Benjamin Franklin originally appeared in Look and Learn issue number 701 published on 21 June 1975.

Benjamin Franklin and his son demonstrating that lightning is simply electricity by Peter Jackson

Ben Franklin was a kindly man, but the turkey had to be killed. Why not do the deed with electricity, he thought. So he caught the big bird and gave it an electric shock.

But something went wrong, for instead of the bird being stunned, Franklin was, knocked unconscious. When he came round, he smiled at his anxious friends and said: “I meant to kill a turkey and instead I nearly killed a goose.”

Anyone less like a silly goose than Benjamin Franklin alleged he was, would be hard to imagine. A master-printer, politician, patriot, postmaster and writer, he yet found time to be a brilliant inventor as well. But then a born inventor seems to have more ideas than the rest of us, and even though some of those ideas turn out to be failures, his mind never stops racing. Franklin’s certainly didn’t, though here we are just concerned with one of his ideas.

The turkey episode, happened in 1752 at his home in Philadelphia, Pennsylvania, when he was 46 years old. Less than two years earlier, he had announced in print that lightning was composed of electricity, the first time that anyone had publicly made so startling a claim. At least one man was interested, a Frenchman named Dalibard, who erected an 80-ft. iron lightning rod in his garden and saw lightning strike it on May 10, 1752, thus proving that the American was right.

It was several months before the news reached Franklin, but by then, he had proved it for himself. On July 4 of that year, during a thunderstorm, he flew a home-made kite which had an iron tip, then rubbed the wet string with a big door key. The string started crackling with electric sparks, although if a severe lightning flash had hit the kite, that would have been the end of Franklin.

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This edited article about magnetism originally appeared in Look and Learn issue number 701 published on 21 June 1975.

Looking at the ship’s compass on the bridge with the captain

The Chinese knew about magnetism more than 4,000 years ago. They found that certain iron ores were magnetic and that bar-shaped pieces of the ore would point in a north-south direction when swung freely.

Arab mariners visiting their shores learned how to make magnets by stroking pieces of iron with lumps of a natural magnetic iron ore called “lodestone”. These magnets could be used in navigation, because when pivoted they too swung into a north-south direction.

The ancient Greeks thought up many theories to try to explain how magnets worked. One of these was that the surface of a magnet was covered with microscopically tiny hooks. The surface of a piece of iron which a magnet attracted was supposed to be covered with tiny rings!

The Greeks also invented the name “magnetism”. They took this name from the country of “Magnesia,” in Asia Minor, where the natural magnet called lodestone was found.

And the name “lodestone” itself originally came from “lead-stone” – because compasses made from magnetic materials could “lead” somebody in a given direction.

The first serious scientific study of magnets and how they worked was made by William Gilbert, physician to Queen Elizabeth the First.

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This edited article about Alfred Nobel originally appeared in Look and Learn issue number 701 published on 21 June 1975.

Albert Einstein was awarded the Nobel Prize for Physics in 1921

The uneasy conscience of a Swedish scientist, who slowly realised that his life’s work would create destruction and misery, led to the foundation of awards dedicated to the search for peace and the happiness of mankind.

All his life, Alfred Bernhard Nobel, the inventor of dynamite, had investigated the chemical properties that released enormous waves of energy when detonated. His ambition was to make them safe to handle and he visualised his discoveries being used in peaceful pursuits such as blasting out harbours, clearing mines and demolition work of all kinds.

Maybe he was naive or perhaps he never found the time to contemplate the awfulness that his work might one day produce. And it seemed he never realised how much money he was making. His work encompassed his horizons completely.

Alfred Nobel, who was born in Stockholm on October 21, 1833, was brought up in his father’s inventive aura. Emmanuel Nobel was a manufacturer of nitroglycerin and he had a genius for invention but it was not reinforced by training or education. The creative instinct was not restrained by the caution that comes from learning, with the result that many accidents occurred with his experiments with explosives.

Emmanuel went to Russia where he made steamships and underwater explosives for the government. The rest of the Nobel family joined him in St. Petersburg – now Leningrad – in 1842.

Alfred Nobel spent only two terms in school and then tutors were brought in to help him study to become an engineer. He never went to university. But by his 16th birthday, he was a competent chemist and fluent in French, German and Russian with enough knowledge of English to write poetry in the language.

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This edited article about underwater exploration originally appeared in Look and Learn issue number 701 published on 21 June 1975.

Salvage divers by Andrew Howat

Wearing rubber suits and breathing apparatus, two men dived deep into the water off Grand Bahama in the warm West Indies. Propelling themselves by their flippers, they went farther and farther into the green depths to find themselves amid a myriad of strange plants and fishes.

The two explorers in this underwater world were John J. Gruener and R. Neal Watson of the U.S.A., who made a record descent of 437 feet (133 metres) on 14th October, 1968.

Men using chambers to withstand the pressure of the water have gone deeper than this. But they lack the mobility of skin divers like Gruener and Watson. By studying old wreck sites, sunken harbours and inundated cities, these specialised divers are helping historians and archaeologists to gain valuable knowledge about the past.

Divers are specially trained for this work, for clumsy, unskilled probing could ruin a valuable wreck site and destroy something of vital importance. This is because most ships do not remain intact underwater. The wood in them rots away and the metal parts become covered in weed and develop a solid, hardened “skin”.

Each descent brings a surprise, for who knows what the divers will find as they probe the mysteries of the ocean?

This edited article about alchemy originally appeared in Look and Learn issue number 700 published on 14 June 1975.

The Neapolitan Count Caetano dazzled Frederick I of Prussia with his alchemical fireworks which appeared to produce gold

Of all the non-events of the Middle Ages, none was so nonsensical as the practice of alchemy. At a time when simple, illiterate craftsmen were creating the astounding glory of medieval cathedrals, their so-called betters were wasting time trying to change base metals (or anything else that came to hand) into silver and, particularly, gold.

However, we can hardly blame our ancestors, as the “art” of alchemy dates back to the ancient Egyptians, and the great Greek philosopher Aristotle had not helped matters by pronouncing that everything was made up of earth, water, air and fire. Change the mixture of these in a metal, alchemists believed, and another metal could be made, even gold. The mythical substance they sought was the Philosopher’s Stone, and it was not merely gold that would spring from it. Optimists believed that the way would be wide open to curing all illnesses and, best of all, to discover the secret of eternal life.

The first person to challenge all the nonsense publicly was an unlikeable but able Swiss doctor called Paracelcus, an alchemist himself, who, early in the 16th century, publicly burnt earlier “learned” writings and told his fellow gold-seekers to get on with the more important job of improving medicine.

There is a happy ending to this silly story, for along the way a lot of useful knowledge had been gathered incidentally by the alchemists, who were accidentally the fathers of modern chemistry. Using simple trial and error, they learnt much about metals, helped improve ways of smelting iron, found new alloys, which helped bell-founders, clockmakers and others, and the makers of cannon and machinery used in corn mills.

Even alchemist-doctors sometimes found a good remedy, and it is true to say that the borderline between medieval alchemy, chemistry and medicine is hard to define. Which does not alter the fact that alchemy itself was a load of ancient and medieval, British and foreign, rubbish.

This edited article about the moon originally appeared in Look and Learn issue number 700 published on 14 June 1975.

The earth seen from the moon

When you spin a top you give it a smart twist to start it going and then leave it alone.

It is exactly the same with the Earth. It was given its spin when it was formed, 4,500 million years ago, and it turns today only because it has not yet come to a stop.

To see how it spins we must find out how the Earth was made.

One theory is that the Earth came from a vast cloud of tiny particles of rock and metals, all circling round the Sun in separate orbits.

Presently some of the particles jostled against each other and stuck together, and the lump began to grow like a snowball, gathering more and more particles until it became a large, solid ball – the Earth.

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This edited article about animal intelligence originally appeared in Look and Learn issue number 699 published on 7 June 1975.

Tea for four chimps at the zoo by James E McConnell

When, at a very early age, we stood upright and hesitatingly took our first few steps, our parents were probably very proud of us.

After all, we had been trying to walk for quite a number of months. We learned how to crawl and use our complicated system of muscles. Finally came the most difficult lesson of all – standing on two feet and walking.

But let us think about what happens a few minutes after a foal is born. The frail little creature makes a few jerky movements, staggers up on its four spindly little legs – and then walks almost perfectly!

The ability of animals to do many complicated things without apparently having to learn them is called instinct.

Biologists are not at all certain exactly how these animal instincts or “built-in skills” have come about.

In fact some scientists are beginning to think that some instincts are not really built-in at all. Instead of the skill being inherited from the animals’ parents, it might still have been learnt.

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This edited article about thunder and lightning originally appeared in Look and Learn issue number 698 published on 31 May 1975.

The ancient Greeks believed Zeus created thunder and lightning

Our ancestors were terrified by the roll of thunder and the flash of lightning. They thought they were signs of God’s anger.

Today we know better.

Scientists have proved that thunder and lightning are just electricity in the clouds.

Clouds are made up of drops of water and these drops are electrified – probably by radiation from the sun. The strength of electricity in a cloud depends on the size of the drops.

For example, the drops of water in a cumulus cloud, which is the kind of cloud that produces thunderstorms, are eight times larger than the drops in an ordinary cloud.

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