helium

[ hee-lee-uhm ]

noun

1. an inert, gaseous element present in the sun's atmosphere and in natural gas, and also occurring as a radioactive decomposition product, used as a substitute for flammable gases in dirigible balloons. : He; : 4.0026; : 2; density: 0.1785 grams/liter at 0°C and 760 millimeters pressure.

helium

/ ˈhiːlɪəm /

noun

1. See alpha particle
   a very light nonflammable colourless odourless element that is an inert gas, occurring in certain natural gases: used in balloons and in cryogenic research. Symbol: He; atomic no: 2; atomic wt: 4.002602; density: 0.1785 kg/m³; at normal pressures it is liquid down to absolute zero; melting pt: below –272.2°C; boiling pt: –268.90°C See also alpha particle

helium

/ hē′lē-əm /

1. A very lightweight, colorless, odorless element in the noble gas group. Helium occurs in natural gas, in radioactive ores, and in small amounts in the atmosphere. It has the lowest boiling point of any substance and is the second most abundant element in the universe. Helium is used to provide lift for balloons and blimps and to create artificial air that will not react chemically. Atomic number 2; atomic weight 4.0026; boiling point −268.9°C; density at 0°C 0.1785 gram per liter.
2. See Periodic Table

helium

1. A chemical element , usually found in the form of a gas , in which two electrons are in orbit , and the nucleus consists of two protons and two neutrons . Its symbol is He.

Notes

Because it is lighter than air, helium is used to fill balloons.

Helium is the best known of the inert gases.

Word History and Origins

Origin of helium¹

First recorded in 1875–80; from New Latin, from Greek hḗli(os) “the sun” + New Latin -ium noun suffix; -ium

Word History and Origins

Origin of helium¹

C19: New Latin, from helio- + -ium ; named from its having first been detected in the solar spectrum

Word History

The second most abundant element in the universe after hydrogen, Helium (symbol He) is a colorless, odorless, nonmetallic gas that is produced abundantly by the nuclear fusion in all stars and is found in smaller amounts on Earth. It was discovered by the British scientist—and founding editor of the journal Nature —Joseph Norman Lockyer in 1868, while he was studying a solar eclipse with a spectroscope, an instrument that breaks light up into a spectrum. If an element is heated up enough to glow, the emitted light produces a unique spectrum when refracted through a prism. Lockyer noticed that the spectrum of the Sun's corona, which is visible only during a solar eclipse, contained lines produced by an unknown element. He named the element helium from helios, the Greek word for “sun.” Helios gives us many other words pertaining to the Sun, such as heliocentric and perihelion.

Example Sentences

The team behind some of the earlier measurements is now back with a new one, this one tracking the behavior of a muon orbiting a helium nucleus.

From Ars Technica

They could change their altitude to catch different air currents by either pumping air in, or out, of a smaller balloon that was inside the larger helium vessel.

From Popular-Science

These stars were fashioned only from hydrogen and helium, the cosmos’s rawest materials.

From Quanta Magazine

The typical Macy’s parade balloon may use around 12,000 cubic feet of helium, while global consumption is on the order of 6 billion cubic feet per year.

From Popular-Science

The helium absorbed heat from the LEDs as it wound through the channel and expanded until it was finally released through a small nozzle.

From Ars Technica

She added in the high-pitched, over-enunciated voice, like she was alternating between sucking on helium and a bong.

From The Daily Beast

Previously a big, fat tank of liquid helium was needed for the task.

From The Daily Beast

So of course, Jimmy Fallon took the opportunity to ruin it by forcing Freeman to inhale helium and pitch up his voice.

From The Daily Beast

Especially when the one you love has a voice like nails on a helium-soaked chalkboard.

From The Daily Beast

After he inhaled sulfur hexafluoride, a compound that acts like helium, his voice got very deep.

From The Daily Beast

What bug in the new helium process might account for this delay?

From Project Gutenberg

There was only one thing to do, there being only one other gas comparable in lightness to helium.

From Project Gutenberg

An atom of lithium-7 plus an atom of hydrogen-1 yields two atoms of helium-4 and plenty of energy.

From Project Gutenberg

He turned the dial to emergency maximum and gulped precious liters of oxygen-helium mixture.

From Project Gutenberg

When they opened the sample chamber, they got a blast of high-pressure helium right in the face.

From Project Gutenberg