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Discovered : by Sir William Ramsay in London, and independently by P.T. Cleve and N.A. Langlet in Uppsala, Sweden in 1895
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Helium gas is a colourless, odourless, tasteless inert gas at room temperature and makes up about 0.0005% of the air we breathe.
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During World War II, the army and navy funded experimental plants that produced non-explosive helium as a replacement for the explosive hydrogen gas used in observation balloons and airships. Once widely available, the element became crucial in ending the war.
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Manhattan Project scientists used helium to make the atomic bomb. Helium was employed in military hospitals as a lifesaving anesthetic. Soldiers suffering with respiratory diseases were also administered helium.
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Legendary British flying ace Douglas Bader, while recovering from serious wounds sustained during a dogfight over France, was treated with copious amounts of helium. Upon his triumphant return to the skies, Bader reputedly turned to his copilot and said, Hey Ben... Ben...Wanna see my Fokker?
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In the liquid state, it is used to achieve extremely low temperatures in electronic devices or for studies in the region of 0-5 K. Helium is also the adequate gas for low temperature gas thermometers due to its low boiling point and almost ideal behaviour.
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Helium is also used, mixed with oxygen, in asthma treatment because it diffuses very easily through the lungs. It can also be used in respiratory mixtures for high depth divers, because it is less soluble in blood than nitrogen.
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Helium was also found very low quantities in rocks, natural and vulcan ic gases and radioactive minerals. Helium was initially used in dirigible-balloons. Nowadays, is used just like argon, in the production of an inert gaseous atmosphere during magnesium, aluminium and titanium welding; it can be used in the cooling of nuclear reactors as transfer media, since it is an inert gas.
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The discovery of helium in radioactive materials was not totally understood until the discovery of radium in 1898. Then, it was verified that helium was a stable product of the radioactive elements disintegration.
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Some scientists concluded that the helium gas present in Earth had that origin. Some others thought that the origin of helium on Earth was a survival of the "primordial helium".
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Helium has a characteristic and bright spectrum that easily identifies the element. Its bright yellow spectrum stripe, responsible for the discovery of the element, is not hidden by any other element. Scientifically, helium is one of the most important elements.
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A helium atom has two protons in its nucleus and two electrons around it. Helium nuclei were created during the big bang and so are some of the oldest and commonest objects in the Universe. About one quarter of the mass of the Universe is made up of helium atoms!
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Helium has some very unusual properties when it is very cold. It can flow up the walls of containers and escape. It can conduct heat and electricity with almost no resistance, making it a superconductor.
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It is a fact, because of their unreactivity, the noble gases were not discovered until the existence of helium
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Because helium does not burn readily like hydrogen, it is a popular gas for lighter-than-air balloons. Interestingly, we can recognize the presence of helium due to its unusual effects on the vocal chords .
In a helium-rich atmosphere, a person temporarily experiences a high-pitched, squeaky voice. Furthermore, this gas diffuses easily through the lungs, and therefore, it is commonly mixed with oxygen to create an artificial air supply for deep-sea divers.
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Helium never crystallizes at the normal pressure. Quantum fluctuations are strong in Helium due to its low atomic weight. The interaction of Helium atoms is weak since it is a noble gas. As a result, Helium remains liquid even at absolute zero. When cooled to almost absolute zero, it becomes a super fluid. Super fluid Helium has zero viscosity.
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Terrestrial Effects - Ice ages occur periodically on Earth and it has been suggested that reductions in the solar luminosity or some other solar variation may be partially responsible. If this is so, then a helium 3 instability which causes mixing in the solar core at discrete intervals could be the cause of periodic ice ages on Earth.
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The time between theoretical core-mixing episodes in the Sun caused by the helium 3 instability and the intervals between major ice ages on the Earth are roughly similar
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Energy Generation in the Sun - The Sun produces energy by fusing hydrogen to helium. This may be accomplished in a number of ways but in the Sun, a process known as the proton-proton chain is thought to be primarily responsible for energy generation
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Helium in the rocks - Most helium on earth is produced by radioactive decay in rocks. The small atoms of helium gas have no trouble escaping from the rocks into the atmosphere.
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Scientists can work out how fast helium is forming, how fast it escapes from rocks, how much enters the air, and how much can escape from the air into space. They can also measure the amount of helium in rocks and in the air. From this, they can calculate the maximum age of rocks and of the air. The results are puzzling to those who believe in billions of years.
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Of course, all such calculations depend on assumptions about the past, like the starting conditions and constant rates of processes. They can never prove the age of something. For that, we need an eye-witness
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On earth, it is produced mainly by radioactive alpha (a)-decay. The great New Zealand physicist Ernest Rutherford (1871–1937) discovered that a-particles were really the nuclei of helium atoms. Radioactive elements in rocks—like uranium and thorium—produce helium this way, and it leaks out into the air
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Helium in the sun is generally believed to be formed by nuclear fusion. This is where nuclei of hydrogen, the lightest element, combine to form helium with huge amounts of energy released.
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Helium is the second lightest chemical element, with many unique properties. It is so named because it was first detected in light patterns in the sun (Greek helios) before it was detected on earth. All gases will condense into a liquid if cooled enough, but helium has the lowest condensation point of any substance (–269°C or –452°F).
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Unlike other elements, it will never freeze, no matter how cold it is, except under high pressure.1 Also, liquid helium cooled below –271°C (–456°F) forms a unique phase called a super fluid, which flows perfectly, without any resistance (viscosity).2
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We're all familiar with helium, the very light gas that makes balloons and airships float in the air. Helium has an important safety advantage—it cannot burn or explode like hydrogen. It is also a vital part of air mixtures for breathing by deep-sea divers—unlike nitrogen, it hardly dissolves in blood or lipids (fatty compounds) even at high pressures
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This avoids nitrogen narcosis, where the nervous system (60% lipid) becomes saturated with nitrogen, which can make divers feel as if they had consumed one martini per 100 ft of depth. It also avoid the bends or decompression sickness, a painful and dangerous condition caused by nitrogen bubbles forming in the diver’s blood, nervous system, joints, and under the skin, if the pressure drops too fast as the diver re-surfaces.
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The helium/oxygen mixture (heliox) makes the voice very high-pitched, because sound travels much faster in helium than in air—a favourite party trick using helium-filled balloons.
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So why are helium and hydrogen so much lighter than air? It's because the hydrogen and helium atoms are lighter than a nitrogen atom. They have fewer electrons, protons and neutrons than nitrogen atoms do, and that makes them lighter (the approximate atomic weight of hydrogen is 1, helium is 4 and nitrogen is 14).
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Approximately the same number of atoms of each of these elements fills approximately the same amount of space. Therefore, the gases made of lighter atoms are lighter.
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