Making light of helium
Known best for making balloons float, this element’s uses are surprisingly versatile
Floating in a party balloon, helium seems like harmless fun – but you also find it at the furthest extremes of heat and cold. Helium is the second-simplest chemical element: each atom is built from just two protons, two neutrons and two electrons. It can be created when four atoms of the very simplest element, hydrogen, which has one proton and one electron, fuse together. Hydrogen transforms like this in the hot, dense conditions we find in stars like the Sun. The hydrogen-to-helium nuclear fusion process creates the awesome power that takes the Sun’s core temperature to around 15 million degrees Celsius.
Being made in this way, helium is the second most abundant element in the universe after hydrogen. But here on
Earth, it’s surprisingly rare. The combination of two protons, two neutrons and two electrons give it properties that mean it doesn’t stick around for long, including in the lightness so prized in balloons. Being so lightweight, it can easily escape the planet’s gravitational pull and drift out into space. It’s also chemically very stable, so doesn’t react easily with other heavier substances that might keep it on Earth. That stability is what makes helium preferable for use in balloons to hydrogen, which is lighter still, but burns easily and dangerously.
What’s even more useful about helium is that despite being born from the fiery heart of stars, it can be the coldest thing on Earth. Changing it from gas to liquid means cooling it below its boiling point of -268.9 degrees Celsius. This makes helium very valuable for accessing properties that only show up when materials are this cold. For example, it allows us to use superconductor materials that can be very strong magnets, found in MRI scanners. For such a lightweight element, helium has a heavyweight impact when used like this.
“Helium is the second most abundant element in the universe”