Helium Gas Explained for Kids: Definition, Uses, and Lesser-known Facts

Have you ever let go of a balloon and watched it float away? That's helium doing its thing. It's a pretty fascinating gas when you think about it. It exists in stars, it makes your voice go squeaky, and doctors actually need it to run hospital machines. Let's break it all down in simple terms.

What Exactly Is Helium?

Helium is a type of gas. Its symbol is “He,” and it sits at number 2 on the periodic table. It belongs to a group called noble gases, which means it doesn’t easily mix or react with other substances. You can’t see, smell, or taste it, and it is generally safe to be around in normal amounts.

Helium is actually the second most common element in the whole universe, after hydrogen. But on Earth, it’s not that easy to find. Most of the helium we use comes from deep underground. It forms very slowly over millions of years when certain natural materials break down. Companies usually collect it while drilling for natural gas.

The reason helium balloons float is simple: helium is way lighter than air. One litre of air weighs about 1.2 grams. One litre of helium? Just 0.164 grams. A balloon filled with helium rises because it is so much lighter than anything around it. 

Before we continue, one more interesting fact: helium was discovered on the Sun before it was discovered on Earth. While researching sunlight in 1868, scientists saw something they couldn't quite put their finger on. They named it "helium" after Helios, the Greek god of the Sun. It took another 27 years before someone found it here on Earth.

The Many Uses of Helium

Helium does far more than just fill party balloons. Here are a few of its most significant applications: 

Balloons & Airships

The obvious ones are balloons and blimps. Since helium is lighter than air and, unlike hydrogen, it doesn't catch fire, it's the safe choice for floating things.

MRI Machines

MRI machines in hospitals need helium badly. Those big scanning machines use powerful magnets that have to stay extremely cold to work. Liquid helium keeps them at the right temperature. Without helium, MRI machines simply don't function.

Space Rockets

Space rockets use helium, too. It is injected into fuel tanks to keep the pressure constant. Helium is perfect for this because it doesn't react with rocket fuel and stays calm in extremely cold temperatures. 

Deep-Sea Diving

Deep-sea divers breathe a mix of helium and oxygen called heliox when they go very deep. Regular compressed air at extreme depths becomes dangerous; it can affect the brain, so helium steps in to make the breathing mixture safer.

Welding

Welders use helium as a shielding gas to protect the area they're working on from the air around it, which would otherwise mess up the weld.

Semiconductor Manufacturing

Computer chip factories use helium to create a super-clean environment during production. Helium keeps everything clean since even minute dust particles can destroy a chip. 

Leak Detection

Helium is also used to find leaks. Its particles are very small, so they can slip through tiny holes that other gases might not pass through. Scientists spray helium around pipes or even spaceships, and then use special tools to check where the gas is leaking out.

Lesser-Known Facts About Helium

The Squeaky Voice Effect

Yes, it’s true, and there’s a simple reason for it. When you breathe in helium and speak, sound moves through it much faster than it does through normal air. This changes how your voice comes out, making it sound high-pitched and funny. It's a classic party trick, but fair warning, breathing too much of it is actually dangerous because it pushes out the oxygen your body needs.

The Coldest Liquid

Helium gets colder than anything else on Earth. At -269 °C, its boiling point is only 4 degrees above absolute zero, the lowest temperature that is physically possible. Scientists use liquid helium to cool equipment down to near-absolute-zero for experiments.

We're Running Out

We're slowly running out of usable helium. When helium escapes into the atmosphere, it just keeps going up and eventually drifts into space. Earth's gravity cannot hold it in place. Every balloon that floats away will contain helium that we will never be able to retrieve. Researchers are looking for ways to gather and recycle it before it completely vanishes. 

Superfluidity

One of the strangest things about helium happens when it gets extremely cold. In this state, liquid helium can flow without any resistance at all. It can even climb up the sides of a container and spill over, almost like it’s defying gravity. Scientists still don’t fully understand why this happens.