Helium is most commonly known as the gas used to fill lighter than air balloons. However, helium is more than a novelty and it's getting scarce.
Helium is one of the naturally occurring elements along with other well-known elements like oxygen, iron, carbon, etc. Natural elements are those not created by man — like plutonium or nobelium — or those that are exceedingly rare existing briefly as a result of radioactive decay, like francium. Helium is the second element listed on the periodic table. Only hydrogen — number one — is less dense than helium.
Properties of Helium
Helium is an inert gas, meaning that it does not combine naturally with other elements to form compounds. Since it is inert, a few breaths are sometimes inhaled for entertainment producing a high-pitched unnatural voice as the vocal cords vibrate more rapidly. Breathing nothing but helium for a long period would lead to death due to lack of oxygen.
Because helium is so light compared to air, it is used to fill weather balloons and lighter-than-air craft like blimps. Hydrogen has greater lifting ability but is dangerously flammable. Although rare in the earth’s atmosphere, helium comprises 23% of the mass of material in the universe. Most of it was created minutes after the “Big Bang.” Helium is also produced naturally in the earth in the decay of radioactive elements and in thermonuclear reactions in stars. It escapes rapidly from the earth due to its low density rising through heavier gases of the atmosphere and becoming concentrated about 600 miles above the earth’s surface. Eventually it is blown off into space by the solar wind.
Helium exists as a gas unless cooled to -269 degrees Celsius — just four degrees above absolute zero. Liquid helium can be solidified under high pressure. At two degrees above absolute zero, helium becomes a superfluid — i.e., it loses its resistance to flow. As a superfluid liquid helium can flow up and over the sides of its container or seep through the microscopic pores.
At very low temperatures, liquid helium is also capable of inducing the property of superconductivity causing materials lose their resistance to electrical current. This property has become useful for highly technical devices.
The Discovery of Helium
Helium was discovered in 1868 by Pierre Janssen as he observed a solar eclipse with a spectroscope. Spectroscopic analysis revealed a line of an unknown element which was subsequently named after the Greek name for the sun — Helios. The new element was thought to exist only on the sun.
Sir William Ramsay discovered helium on earth in 1895 as a result of alpha decay in radioactive elements. An alpha particle — consisting of two protons and two neutrons — is simply a helium nucleus, but can be deadly if inhaled or ingested. When the nucleus gathers up a pair of electrons, it becomes ordinary, harmless helium.
Helium was first liquefied in 1908, and by the 1930’s commercial production of liquefied helium began by cooling natural gas. Helium is extremely rare in the atmosphere, but can be found in high concentrations — up to 7% in natural gas — as alpha particles gain electrons forming helium and drift into the same pockets where natural gas is trapped.
Global Helium Shortage
Helium, as a result of it unusual properties, has many special uses — many are highly technological. As technology has grown, helium demand has increased to a point where shortages are common.
Wherever extreme cold is required, helium is likely used. For example, superconductive magnets in MRI’s and devices typically use helium as a coolant. Over 130 tons of liquid helium are used to cool super-magnets in the Large Hadron Collider. Helium is also used in welding, pressurization, and lighter-than-air craft. Large amounts of helium are required worldwide to inflate millions of balloons in florists businesses and gift shops.
The increasing demand for helium has placed great demand on the 15 plants in the world that produce helium and the price is steadily increasing — the retail cost rose 20% to 30%. Its use as a novelty in balloons may cease, as it is non-essential and the price of helium-filled balloons may become too high.
Helium is most often known as the gas used to inflate gift balloons, but it has many special properties that make it useful a variety of technological applications. Demand for helium has grown recently as technology has expanded globally. The price of helium has been rising rapidly and shortages are becoming common.
Sources:
“The Element Helium,” education.jlab.org.
“Helium Facts,” blm.gov