Why do we NEED helium? what is its importance today?

Question

ahhh

oh, and any interesting facets/ human interest stories?

Answer 1

Helium fills balloons, making them float.
We need floating helium-filled balloons to celebrate the birthday parties of children.

Answer 2

Someone I know had an MRI scan recently. The device uses a magnetic field of 15,000 gauss -- several times what is used in a typical electric motor. Such a huge field requires a superconducting magnet for creation, and that means it needs a continuing source of liquid helium, which at 4 K is cold enough to maintain superconductivity. Helium is of course used for balloons, for leak detection in vacuum systems, for pressurizing various substances, and for other purposes. Certain gas wells in Texas are the source of much of the world's helium -- it is a constituent of natural gas from these wells. Helium is light enough that it cannot be retained in the earth's atmosphere but is gradually lost to space.

Answer 3

Helium is used for many purposes that require some of its unique properties, such as its low boiling point, low density, low solubility, high thermal conductivity, or inertness. Pressurized helium is commercially available in large quantities.

Because it is lighter than air, airships and balloons are inflated with helium for lift. In airships, helium is preferred over hydrogen because it is not flammable and has 92.64% of the lifting power of the alternative hydrogen.

For its low solubility in water, the major part of human blood, air mixtures of helium with oxygen and nitrogen (Trimix), with oxygen only (Heliox), with common air (heliair), and with hydrogen and oxygen (hydreliox), are used in deep-sea breathing systems to reduce the high-pressure risk of nitrogen narcosis, decompression sickness, and oxygen toxicity.

At extremely low temperatures, liquid helium is used to cool certain metals to produce superconductivity, such as in superconducting magnets used in magnetic resonance imaging. Helium at low temperatures is also used in cryogenics.

For its inertness and high thermal conductivity, helium is used as a coolant in some nuclear reactors, such as pebble-bed reactors.

Helium is used as a shielding gas in arc welding processes on materials that are contaminated easily by air. It is especially useful in overhead welding, because it is lighter than air and thus floats, whereas other shielding gases sink.

Because it is inert, helium is used as a protective gas in growing silicon and germanium crystals, in titanium and zirconium production, in gas chromatography, and as an atmosphere for protecting historical documents. This property also makes it useful in supersonic wind tunnels.

In rocketry, helium is used as an ullage medium to displace fuel and oxidizers in storage tanks and to condense hydrogen and oxygen to make rocket fuel. It is also used to purge fuel and oxidizer from ground support equipment prior to launch and to pre-cool liquid hydrogen in space vehicles. For example, the Saturn V booster used in the Apollo program needed about 13 million cubic feet (370,000 m³) of helium to launch.

The gain medium of the helium-neon laser is a mixture of helium and neon.

Because it diffuses through solids at a rate three times that of air, helium is used to detect leaks in high-vacuum equipment and high-pressure containers.

Because of its extremely low index of refraction, the use of helium reduces the distorting effects of temperature variations in the space between lenses in some telescopes.

The age of rocks and minerals that contain uranium and thorium, radioactive elements that emit helium nuclei called alpha particles, can be discovered by measuring the level of helium with a process known as helium dating.

Because helium alone is less dense than atmospheric air, it will change the timbre (not pitch) of a person's voice when inhaled. However, inhaling it from a typical commercial source, such as that used to fill balloons, can be dangerous due to the number of contaminants that may be present. These could include trace amount of other gases, in addition to aerosolized lubricating oil.

The high thermal conductivity and sound velocity of helium is also desirable in thermoacoustic refrigeration. The inertness of helium adds to the environmental advantage of this technology over conventional refrigeration systems which may contribute to ozone depleting and global warming effects.