Here’s what most of us know about helium: It lets balloons float into the sky even after you said to hold on tight, and it can make our voices sound really high and squeaky.

All of which could make helium the laughingstock of the periodic table of elements — literally, He He He — except that it’s also crucial to some very serious tasks.

It cools magnets that run MRI machines and make semiconductors for cellphones, eases breathing conditions for deep-sea divers, aids welders and is used in some airport scanners. Helium floats the Goodyear blimp, enabling us to see curiously pointless bird’s-eye views of football fields. It inspires some people — although face it, they’ve pretty much all been guys — to tie balloons to lawn chairs and ascend into wild blue flight paths. Plus, Pixar’s “Up” was a heckuva movie.

So word of a helium shortage gives pause. Have we seen the last inflatable gorilla bobbing over a car dealership? The tricky thing is that word, shortage.

There actually is plenty of helium on Earth. In fact, it’s the second most abundant element in the universe, after hydrogen. But it’s a byproduct of natural gas production, so when natural gas prices are at historic lows, as they’ve been, production of both gases declines.

“There are so many factors that enter into the supply,” said Kristin Traynor, who owns the Corner Balloon Shoppe in Minneapolis. She said she’s been able to get enough helium, but has had to pay a bit more. “We had to raise our prices just a little bit, but got no comment from people.”

However, she added that her supplier no longer is accepting new customers.

A supply crunch last fall led to some shortages at balloon shops, for several reasons. Helium plants in Wyoming and Texas were shut down for maintenance that took longer than expected. Plants in Algeria and Qatar slowed production because of low prices. Nature played a role, as well.

“Even the wildfires out west affected plants,” Traynor said. “Up until three years ago when I bought the shop, I never thought twice about helium. Why would you?”

Helium everywhere, but …

The United States once had a huge reserve of helium until, according to an excellent recap in Popular Mechanics, Congress decided in 1996 to privatize the program. It called for the government’s supplies to be sold off by 2015, figuring that new sources of helium would be developed. But, much as Minnesota legislators learned that no one was clamoring for e-pulltabs, so the feds learned that industry wasn’t straining at the bit to produce helium.

So, we’re playing catch-up in the face of dwindling supplies. There’s still helium in reserve, but it’s being rationed until new production plants open in the next few years.

Robert Hanson, a professor of chemistry at St. Olaf College in Northfield, has a knack for explaining to those who aren’t chemistry professors why helium is necessary.

Helium’s special property is that it has a very low boiling point — minus 452 degrees F. — or in Hanson’s world, 4 degrees Kelvin.

“One of the properties of a liquid is that when it boils, it will sit there at that boiling point and never go any higher,” Hanson said. Just as water never gets hotter than 212 degrees, so helium will stay at that temperature, making it an excellent cooling product.

“We have instruments around here with superconducting magnets that have to be kept at 4 degrees Kelvin, so the helium acts as a sort of super-thermos around these coils,” he said, adding that while St. Olaf hasn’t had trouble getting supplies of helium, it has cost more.

Hanson noted efforts to find alternatives to helium — especially Helium-3, which detects neutron radiation, making it valuable to the folks at Homeland Security. But scientists also use Helium-3 to gain “incredible images of what’s in your lungs” when inhaled. “That’s the helium that has really skyrocketed in price.”

With prices rising, Hanson said, more hospitals and research institutes are recycling helium. “It’s a fairly new technology and costs a lot of electricity,” but bolsters the supply.

Science vs. silliness

Scientific and medical uses of helium take priority, as they should, so helium’s more inventive uses may ebb.

Take the University of Nebraska’s 70-year tradition of fans releasing up to 5,000 red balloons when the team first scores. Concerns last fall over helium supplies at local hospitals put the spectacle on hiatus. Once school officials learned the shortage wasn’t dire, they reinstated the release, but with only 2,000 balloons per game.

Or how about the Eternal Ascent Society? The Florida company places cremated remains in a 5-foot-tall, biodegradable balloon. Inflated with helium, the balloon is released “to the heavens,” where it ascends to about 30,000 feet, at which height it freezes and cracks open, scattering the ashes. Its president, Joanie West, said helium prices have doubled, which hasn’t helped her business.

No story about helium can pass without a nod to Lawrence Richard Walters, a k a “Lawnchair Larry.” In 1982, he took to the California sky in a lawn chair to which he’d tied 45 helium-filled weather balloons. He rose about 3 miles, and descended safely, but never really came back to Earth, committing suicide in 1993. Today, cluster ballooning is an extreme sport (www.clusterballoon.org).

Finally, there is helium’s most curious attribute: its ability to make our voices go all Mickey Mouse when we inhale it.

Here’s the science: The vocal cords in our larynx vibrate when air passes between them. Helium is less dense than air, so sound travels faster through it. When you take a few puffs from a helium balloon, then talk, your vocal cords vibrate more quickly, sending the pitch of your voice much higher than normal.

Of course, there’s now an app for this. Record your voice, move your finger over the app’s helium balloon to change its pitch, then upload it to SoundCloud.com.

Just don’t be surprised if someone decides to declare you in short supply.