Odorless, colorless and lighter than air, helium is classified on the periodic table as one of the noble gases. Even though it was abundant in the universe, it was completely unknown for most of human history, for many reasons. Learn more about the second most abundant element in the universe.
Helium and Hydrogen
Helium (symbol He) is unique. In 1868, helium was a mystery in much the same way as dark matter is today. It was a substance not seen and not found in any compound on Earth.
The sun has an immense gravitational force. It pulls hydrogen atoms together and, by a process called fusion, helium is formed and energy is released. Fusion is the most powerful reaction in the universe. People have copied it to make thermonuclear (hydrogen) bombs. The force gives off radiation but when it reaches Earth, it is minor and brings sunlight and visible rays.
After hydrogen, helium is the most abundant element on Earth, making up about 24 percent of the galactic stellar mass.
In the inner region of a star, four hydrogen atoms are converted into one helium atom. The sun converts 600 million tons of hydrogen each second, creating 400 million tons of helium.
Scientists can tell what elements make up a substance by looking at the light it gives out when heated. Each element has a unique “spectrum" that can readily be picked out by an instrument called a spectrometer. In the middle of the 18th century, they could identify all the wavelengths from the sun, except for a mysterious yellow light. This was helium.
According to the element’s table, helium is one of 92 elements that cannot be broken down by any known means.
- Is lighter than air
- Is an inert gas
- Rarely reacts
- Cannot burn
- Has boiling and melting points lowest among all elements
- In 1868, astronomers Pierre Janssen and Norman Lockyer observed the spectral line in sunlight first, but could not identify it.
Helium was discovered in a sample of rock—a radioactive uranium-rich mineral—in 1895 by William Ramsay, a Scottish scientist. Ramsay also went on to discover all the other noble gases: neon, argon, krypton, xenon and radon. When electric current is run through a tube of helium, yellow “neon" light is seen.
Helium is named after the Greek word “helios" meaning sun, because the gas was first observed in the sun. (Our first extraterrestrial chemical!)
Most elements react with one another because the combined atoms are more stable than individual atoms. Reactions occur so that atoms can achieve eight electrons, either by losing them or by gaining them from a partner. The noble gases are so stable and react so little because the electrons in the outer part of the atom completely fill the shell. Helium has two atoms.
In 1903, large reservoirs of helium were found in U.S. natural gas fields. The U.S. Bureau of Land Management operates the Federal Helium Reserve near Amarillo, Texas. It holds over 40 percent of the helium used annually in the United States.
Uses for Helium
Because of its extremely low boiling temperature—just four degrees above absolute zero—liquid helium is the standard coolant for superconducting magnets used in MRI (magnetic resonance imaging) devices and particle accelerators.
At very low temperatures helium behaves strangely, having an ability to conduct heat 600 times as well as copper, flowing uphill, climbing up and over the walls of the flask containing it and moving without friction and going through the tiniest of holes.
Helium is also important for deep-sea divers at a mixture of 80 percent helium to 20 percent oxygen—to prevent too much oxygen from entering the brain and for welders—to reduce oxidation during the application of high temperatures. It is also used for rocket launchers, lasers, weather balloons and leak detection.
It is the best refrigerant in the universe. Helium is used on space shuttles to cool the hydrogen and oxygen fuels, both of which have to be kept liquid in the journey.
The world’s first airline was made up of flying balloons. An aerostat is a lighter-than-air aircraft that gains its lift from large gas bags filled with a lifting gas that is less dense than the surrounding air. Dozens of airship explosions occurred because they used hydrogen to fill the dirigibles or zeppelins.
The most visible disaster was the Hindenburg, which took place at Lakehurst, New Jersey on May 6, 1937. For more than 30 years, passengers had traveled on commercial zeppelins, but the era ended in a fiery disaster. An electrostatic charge—a spark—ignited leaking hydrogen and brought the giant airship down in fire.
Balloons over Broadway
You may use helium to fill party balloons that float upward. Every year you watch the Macy’s Thanksgiving Day Parade where gigantic balloon animals fly over the streets in New York City. That happened because of a man named Tony Sarg, an illustrator and puppeteer. Sarg created scenes using mechanized marionettes for Macy’s Herald Square window.
Soon his idea inspired a parade where he had horse-drawn floats with large papier-mâché animals (including actual live beasts in cages). The children were frightened and the people in the back rows couldn’t see, so Tony came up with a better idea. Rubberized air balloons. Eventually the balloons were made with nylon and filled with helium. They were also released to the sky. Of course, that had to be curbed after wayward gigantic balloons created fighting and accidents. As of 2010, it took 300,000 cubic feet of helium to float the 15 character balloons in that year's Macy's Thanksgiving Day Parade.
Minnie Mouse Voice
We have all done it, inhaled air from a helium balloon and turned our voices into a squeak box. Air travels from your lungs to talk. It pushes through your larynx, vocal folds, and out of your mouth. The air is making your vocal cords vibrate. You move your tongue, lips and mouth to form sound and words.
The low density of inhaling helium doesn’t really make your vocal cords vibrate faster, but it does affect the quality of the sound because the lighter-than-air molecules rise, changing the tone quality by allowing sound to travel faster.
Doing this repeatedly is not healthy. You are not getting the oxygen you need and it can cause asphyxiation in minutes. Breathing helium can kill you by rupturing a lung or putting gas in your bloodstream causing a stroke, seizure and death.
Superfluids are liquids that behave as if they have no viscosity, or resistance to flow. “When atoms come together in a superfluid state, they all of the sudden behave as one object," said Oliver Gessner, a senior scientist at the Ultrafast X-ray Science Laboratory at Lawrence Berkeley National Lab, and one of the lead researchers on a project that delved into superfluid helium and observed some very bizarre behavior they still marvel over.
- Sweet, Melissa. Balloons Over Broadway, Boston, New York: Houghton Mifflin Harcourt, 2011. Book.
- Knapp, Brian, BSc, PhD. Hydrogen and the Noble Gases. Danbury, CT: Grolier Educational, 1997. Book.
- Pickover, Clifford A. The Physics Book: From the Big Bang to Quantum Resurrection, 250 Milestones in the History of Physics. New York: Sterling Publishing, 2011. Book.